Backports 2.7

[engechas]

Description of changes:

• Backports #900, #1097, #1302, #1355, #1435, #1441, #1445, #1430
• Fixes BWC tests

CheckList:

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

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.45172% with 95 lines in your changes are missing coverage. Please review.

Project coverage is 77.22%. Comparing base (65c3d3a) to head (cb1e89e). Report is 3 commits behind head on 2.7.

Files	Patch %	Lines
.../opensearch/alerting/DocumentLevelMonitorRunner.kt	83.67%	31 Missing and 25 partials :warning:
...opensearch/alerting/util/DocLevelMonitorQueries.kt	84.75%	7 Missing and 18 partials :warning:
.../org/opensearch/alerting/MonitorMetadataService.kt	37.50%	0 Missing and 5 partials :warning:
.../kotlin/org/opensearch/alerting/util/IndexUtils.kt	72.22%	1 Missing and 4 partials :warning:
...in/org/opensearch/alerting/MonitorRunnerService.kt	90.90%	2 Missing :warning:
.../alerting/transport/TransportIndexMonitorAction.kt	66.66%	0 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## 2.7 #1482 +/- ## ============================================ + Coverage 76.65% 77.22% +0.56% Complexity 116 116 ============================================ Files 125 125 Lines 7257 7684 +427 Branches 1050 1122 +72 ============================================ + Hits 5563 5934 +371 - Misses 1160 1179 +19 - Partials 534 571 +37 ```

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