Updating default compression level for ZStandard Codecs

[sarthakaggarwal97]

Description

This PR is to update the default ZStandard compression level to 3 based on the performance gains we are observing over here at #7555

Related Issues

Resolves:
Optimization mentioned at #7555

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)

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.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/19228/
• CommitID: 47c99eb
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/19229/
• CommitID: 904a7b1
  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 (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.cluster.allocation.AwarenessAllocationIT.testThreeZoneOneReplicaWithForceZoneValueAndLoadAwareness
      1 org.opensearch.action.admin.cluster.node.tasks.ResourceAwareTasksTests.testBasicTaskResourceTracking

• URL: https://build.ci.opensearch.org/job/gradle-check/19233/
• CommitID: 6dde2cc
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Merging #8471 (6dde2cc) into main (8bebf5b) will increase coverage by 0.09%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #8471      +/-   ##
============================================
+ Coverage     70.84%   70.94%   +0.09%     
- Complexity    56935    56954      +19     
============================================
  Files          4758     4758              
  Lines        269219   269219              
  Branches      39407    39407              
============================================
+ Hits         190740   191007     +267     
+ Misses        62416    62126     -290     
- Partials      16063    16086      +23     

Impacted Files	Coverage Δ
.../index/codec/customcodecs/Lucene95CustomCodec.java	76.92% <ø> (ø)

... and 451 files with indirect coverage changes