[APM] Deprecate apm_oss.indexPattern config option

[sorenlouv]

Closes #110733

This PR removes the need for apm_oss.indexPattern by constructing it by concatenating the specified indicies.

This test illustrates it pretty well:
https://github.com/elastic/kibana/blob/47c10042787238661527e46a6cf9dde684b61cd6/x-pack/plugins/apm/server/lib/index_pattern/get_apm_index_pattern_title.test.ts

Having apm_oss.indexPattern was problematic because it forced end users to keep this value in sync with their specified indicies. A user wanted to enable CCS and updated their index settings via the ui but forgot to update apm_oss.indexPattern which caused the search bar and Discover to not work as expected. Without a hardcoded value this won't happen.

[sorenlouv]

I think this is how the option should be deprecated.

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[sorenlouv]

@elasticmachine merge upstream

[kibanamachine]

💛 Build succeeded, but was flaky

• continuous-integration/kibana-ci/pull-request

• Commit: 8ae4155

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• Flaky suites:

  • xpack-kibana-ciGroup5

---

Test Failures

Kibana Pipeline / general / X-Pack Alerting API Integration Tests.x-pack/test/alerting_api_integration/security_and_spaces/tests/alerting/get·ts.alerting api integration security and spaces enabled Alerts alerts get "after each" hook for "shouldn't get alert from another space"

Link to Jenkins

Standard Out

Failed Tests Reporter:
  - Test has not failed recently on tracked branches

[00:00:00]       │
[00:00:00]         └-: alerting api integration security and spaces enabled
[00:00:00]           └-> "before all" hook in "alerting api integration security and spaces enabled"
[00:03:59]           └-: Alerts
[00:03:59]             └-> "before all" hook in "Alerts"
[00:05:25]             └-: alerts
[00:05:25]               └-> "before all" hook in "alerts"
[00:05:25]               └-> "before all" hook in "alerts"
[00:05:25]                 │ debg creating space
[00:05:26]                 │ debg created space
[00:05:26]                 │ debg creating space
[00:05:27]                 │ debg created space
[00:05:27]                 │ debg creating space
[00:05:28]                 │ debg created space
[00:05:28]                 │ debg creating user no_kibana_privileges
[00:05:28]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [no_kibana_privileges]
[00:05:28]                 │ debg created user no_kibana_privileges
[00:05:28]                 │ debg creating role no_kibana_privileges
[00:05:28]                 │ info [o.e.x.s.a.r.TransportPutRoleAction] [node-01] added role [no_kibana_privileges]
[00:05:28]                 │ debg creating user superuser
[00:05:28]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [superuser]
[00:05:28]                 │ debg created user superuser
[00:05:28]                 │ debg creating user global_read
[00:05:28]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [global_read]
[00:05:28]                 │ debg created user global_read
[00:05:28]                 │ debg creating role global_read_role
[00:05:28]                 │ info [o.e.x.s.a.r.TransportPutRoleAction] [node-01] added role [global_read_role]
[00:05:28]                 │ debg creating user space_1_all
[00:05:29]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [space_1_all]
[00:05:29]                 │ debg created user space_1_all
[00:05:29]                 │ debg creating role space_1_all_role
[00:05:29]                 │ info [o.e.x.s.a.r.TransportPutRoleAction] [node-01] added role [space_1_all_role]
[00:05:29]                 │ debg creating user space_1_all_with_restricted_fixture
[00:05:29]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [space_1_all_with_restricted_fixture]
[00:05:29]                 │ debg created user space_1_all_with_restricted_fixture
[00:05:29]                 │ debg creating role space_1_all_with_restricted_fixture_role
[00:05:29]                 │ info [o.e.x.s.a.r.TransportPutRoleAction] [node-01] added role [space_1_all_with_restricted_fixture_role]
[00:05:29]                 │ debg creating user space_1_all_alerts_none_actions
[00:05:29]                 │ info [o.e.x.s.a.u.TransportPutUserAction] [node-01] added user [space_1_all_alerts_none_actions]
[00:05:29]                 │ debg created user space_1_all_alerts_none_actions
[00:05:29]                 │ debg creating role space_1_all_alerts_none_actions_role
[00:05:29]                 │ info [o.e.x.s.a.r.TransportPutRoleAction] [node-01] added role [space_1_all_alerts_none_actions_role]
[00:10:11]               └-: get
[00:10:11]                 └-> "before all" hook in "get"

Stack Trace

Error: expected 204 "No Content", got 409 "Conflict"
    at Test._assertStatus (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/lib/test.js:268:12)
    at Test._assertFunction (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/lib/test.js:283:11)
    at Test.assert (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/lib/test.js:173:18)
    at assert (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/lib/test.js:131:12)
    at /dev/shm/workspace/parallel/19/kibana/node_modules/supertest/lib/test.js:128:5
    at Test.Request.callback (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/node_modules/superagent/lib/node/index.js:718:3)
    at /dev/shm/workspace/parallel/19/kibana/node_modules/supertest/node_modules/superagent/lib/node/index.js:906:18
    at IncomingMessage.<anonymous> (/dev/shm/workspace/parallel/19/kibana/node_modules/supertest/node_modules/superagent/lib/node/parsers/json.js:19:7)
    at endReadableNT (internal/streams/readable.js:1317:12)
    at processTicksAndRejections (internal/process/task_queues.js:82:21)

---

Metrics [docs]

✅ unchanged

History

• 💔 Build #151252 failed e28f05d
• 💚 Build #151042 succeeded 47c1004
• 💚 Build #150948 succeeded 3ee9880

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.