[Backport 2.x] Require MediaType in Strings.toString API (#6009)

[nknize]

Backport 1f4cdd2 from #6009

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/11505/
• CommitID: a5fd954
  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?

[Poojita-Raj]

Hey @nknize, seems like it failed on a related error:

Task :server:compileJava
/var/jenkins/workspace/gradle-check/search/server/src/main/java/org/opensearch/action/admin/indices/replication/SegmentReplicationStatsResponse.java:97: error: incompatible types: SegmentReplicationStatsResponse cannot be converted to MediaType
return Strings.toString(this, true, true);

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/11506/
• CommitID: 1ec4dfb

[codecov-commenter]

Codecov Report

Merging #6414 (1ec4dfb) into 2.x (8b3409e) will increase coverage by 0.01%.
The diff coverage is 27.55%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@             Coverage Diff              @@
##                2.x    #6414      +/-   ##
============================================
+ Coverage     70.34%   70.36%   +0.01%     
- Complexity    59187    59228      +41     
============================================
  Files          4798     4798              
  Lines        284176   284178       +2     
  Branches      41313    41313              
============================================
+ Hits         199899   199952      +53     
+ Misses        67562    67471      -91     
- Partials      16715    16755      +40     

Impacted Files	Coverage Δ
...opensearch/client/slm/SnapshotLifecyclePolicy.java	0.00% <0.00%> (ø)
...ch/client/slm/SnapshotLifecyclePolicyMetadata.java	0.00% <0.00%> (ø)
.../opensearch/client/slm/SnapshotLifecycleStats.java	0.00% <0.00%> (ø)
...rch/client/slm/SnapshotRetentionConfiguration.java	0.00% <0.00%> (ø)
...java/org/opensearch/common/xcontent/MediaType.java	100.00% <ø> (ø)
...a/org/opensearch/common/xcontent/XContentType.java	100.00% <ø> (ø)
...h/script/mustache/MultiSearchTemplateResponse.java	56.25% <0.00%> (ø)
...rg/opensearch/index/rankeval/RankEvalResponse.java	98.57% <0.00%> (ø)
...va/org/opensearch/index/rankeval/RankEvalSpec.java	96.49% <0.00%> (ø)
...a/org/opensearch/index/rankeval/RatedDocument.java	81.03% <0.00%> (ø)
... and 574 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.