Make IndexStoreListener a pluggable interface

[jed326]

Description

I have a use case where I have a custom file cache implementation and in order to not have dangling entries in my fc I need to implement IndexStoreListener to clean up my file cache when shards move off a node. Today that is not possible as IndexStoreListener is an @opensearch.internal interface and not pluggable, which this PR changes.

Long term I think the solution is to make the FileCache itself pluggable, but that is much more complicated and anyways would require us to expose this interface as pluggable, so I believe this is a useful intermediary step.

The other thing to note is in Node.java I am now creating the CompositeIndexStoreListener regardless of if it isSearchNode() or not as it should be up to the specific listener implementations to determine how/when to perform their action.

Check List

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

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[jed326]

@andrross @bugmakerrrrrr @sohami could you review this PR as it is related to #11443?

[github-actions[bot]]

:x: Gradle check result for 8c4fd86a989eb51ff3090541f1fe25417d70a85b: 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[bot]]

:x: Gradle check result for ceeb08ab48a27c2da9225141073b31bfbafba6ac: 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[bot]]

:x: Gradle check result for 65497a053b9ed432a3620cc865273ddcaf9693e6: 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[bot]]

:white_check_mark: Gradle check result for 2de2403420fd5495ccd379a6d3f13256c672bb20: SUCCESS

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 87.50000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 72.11%. Comparing base (034bd2b) to head (ca32a2f). Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...org/opensearch/index/store/IndexStoreListener.java	80.95%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #16583 +/- ## ============================================ + Coverage 72.04% 72.11% +0.07% - Complexity 65093 65102 +9 ============================================ Files 5314 5315 +1 Lines 303541 303572 +31 Branches 43921 43925 +4 ============================================ + Hits 218683 218935 +252 + Misses 66946 66672 -274 - Partials 17912 17965 +53 ```

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[sohami]

lgtm. Will wait for others to approve as well

[github-actions[bot]]

:grey_exclamation: Gradle check result for ca32a2f85b36a99d93d757b0b01cee169a084dbf: 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.