Add node-left metric

[bhumikasharma29]

Description

This PR will add a metric when there is a node drop. The tag will contain details about the node that as dropped and the reason for it.
Continues from #17949

Related Issues

None

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

✅ Gradle check result for d8af721: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 72.74%. Comparing base (f048bb4) to head (a3638cd).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...g/opensearch/cluster/coordination/Coordinator.java	90.90%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #18421   +/-   ##
=========================================
  Coverage     72.74%   72.74%           
- Complexity    68132    68167   +35     
=========================================
  Files          5537     5537           
  Lines        313312   313324   +12     
  Branches      45460    45461    +1     
=========================================
+ Hits         227921   227942   +21     
+ Misses        66873    66843   -30     
- Partials      18518    18539   +21     

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[github-actions]

✅ Gradle check result for 04fff47: SUCCESS

[github-actions]

✅ Gradle check result for 04ddf96: SUCCESS

[github-actions]

❌ Gradle check result for 8118c92: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for a94c5af: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[Gaganjuneja]

Build is failing for spotless. Please fix.

[github-actions]

❌ Gradle check result for 301b9c7: FAILURE

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[github-actions]

❌ Gradle check result for baaa386: FAILURE

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[github-actions]

✅ Gradle check result for 569888a: SUCCESS

[github-actions]

✅ Gradle check result for 91bea5d: SUCCESS

[github-actions]

✅ Gradle check result for ff8d798: SUCCESS

[github-actions]

❌ Gradle check result for 00cab2a: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[bhumikasharma29]

flaky test - #18476

[github-actions]

❌ Gradle check result for f7c3205: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[bhumikasharma29]

flaky test - #18485

[github-actions]

❌ Gradle check result for 6f560bd: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❕ Gradle check result for a3638cd: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[bhumikasharma29]

flaky test has failed - #14310