[Meta]: Get rid of at() matcher in phpunit tests

[come-nc]

See sebastianbergmann/phpunit#4297

• apps/dav - 116
  • Most of it - Get rid of deprecated at matcher in dav application tests #36026
  • Last one - Remove last at matcher call in dav application tests #40424
• apps/encryption - 15 - Remove at() matcher use from encryption tests #32567
• apps/federatedfilesharing - 1 - Remove at() matcher from tests in federatedfilesharing #32570
• apps/files - 6 - Remove at() matcher for tests for files app #32571
• apps/files_sharing - 17 - Remove at() matcher in files_sharing tests #32577
• apps/notifications - 2 - Remove deprecated at matcher from tests notifications#1240
• apps/oauth2 - 1 - Remove at matchers from tests in oauth2 and tests/Test #33435
• apps/provisioning_api - 6 - Fix exception handling when profile data is too long #32799
• apps/settings - 18 - Remove deprecated at() matcher from settings tests #32737
• apps/theming - 49 - Remove at matcher in theming tests #32900
• apps/updatenotification - 1
• apps/user_ldap - 36 - Remove deprecated at() matcher from user_ldap tests #32861
• tests/Core - 39
  • First part - Fix a bunch of deprecation in the phpunit for core #32572
  • Last one - Remove last calls to deprecated at matcher in tests/Core #40420
• tests/Test - 7 - Remove at matchers from tests in oauth2 and tests/Test #33435
• tests/lib - 196
  • First part - Remove at matcher uses in tests/lib #32901
  • Second part - Remove deprecated at matcher in tests/lib part 2 #33732
  • Last one - Remove deprecated at matcher in tests/lib/InstallerTest.php #40419

[joshtrichards]

Still open due to this TODO item: #32577 (comment)

server/apps/files_sharing/tests/External/ManagerTest.php

Line 257 in 7362ede

$this->clientService->expects($this->at(0))