Add setting to limit per alert action executions and don't save Alerts for test Bucket-Level Monitors

[qreshi]

Signed-off-by: Mohammad Qureshi qreshi@amazon.com

Issue #, if available: #86

Description of changes:

• Adds a setting for max actionable Alerts when using PER_ALERT Action execution scope for Bucket-Level Alerting, if this value is exceeded, the Action execution will fallback to PER_EXECUTION scope regardless of the Action configuration
• Adds check to skip saving Alerts for test Monitors (similar to what is already done in the Query-Level Monitor execution)

CheckList:
[x] Commits are signed per the DCO using --signoff

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[codecov-commenter]

Codecov Report

Merging #161 (b2f0c9d) into main (ff57c54) will decrease coverage by 1.79%.
The diff coverage is 72.55%.

@@             Coverage Diff              @@
##               main     #161      +/-   ##
============================================
- Coverage     80.46%   78.67%   -1.80%     
+ Complexity      215      214       -1     
============================================
  Files           154      172      +18     
  Lines          5873     6937    +1064     
  Branches        706      901     +195     
============================================
+ Hits           4726     5458     +732     
- Misses          768      990     +222     
- Partials        379      489     +110     

Impacted Files	Coverage Δ
...in/org/opensearch/alerting/script/TriggerScript.kt	100.00% <ø> (ø)
...nsearch/alerting/script/TriggerExecutionContext.kt	43.75% <11.11%> (-46.25%)	⬇️
...ation/bucketselectorext/BucketSelectorExtFilter.kt	41.53% <41.53%> (ø)
...n/bucketselectorext/BucketSelectorExtAggregator.kt	51.38% <51.38%> (ø)
...egation/bucketselectorext/BucketSelectorIndices.kt	52.38% <52.38%> (ø)
...selectorext/BucketSelectorExtAggregationBuilder.kt	55.90% <55.90%> (ø)
...main/kotlin/org/opensearch/alerting/model/Alert.kt	82.47% <57.44%> (-7.21%)	⬇️
...lin/org/opensearch/alerting/model/action/Action.kt	83.33% <66.66%> (+8.33%)	⬆️
...lerting/transport/TransportExecuteMonitorAction.kt	73.33% <66.66%> (+1.24%)	⬆️
.../org/opensearch/alerting/model/TriggerRunResult.kt	68.75% <68.75%> (ø)
... and 45 more

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