[Backport] [2.4] Use BuildParams.isCi() instead of checking env var (#5368)

[reta]

Backport of #5368 to 2.4

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/7319/
• CommitID: 7dec461

[codecov-commenter]

Codecov Report

Merging #5373 (7dec461) into 2.4 (7c5aa1f) will increase coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                2.4    #5373      +/-   ##
============================================
+ Coverage     70.64%   70.70%   +0.06%     
- Complexity    58303    58321      +18     
============================================
  Files          4696     4696              
  Lines        278890   278890              
  Branches      40737    40737              
============================================
+ Hits         197011   197188     +177     
+ Misses        65458    65252     -206     
- Partials      16421    16450      +29     

Impacted Files	Coverage Δ
...a/org/opensearch/client/cluster/SniffModeInfo.java	0.00% <0.00%> (-56.25%)	⬇️
.../java/org/opensearch/search/dfs/AggregatedDfs.java	51.61% <0.00%> (-45.17%)	⬇️
.../org/opensearch/client/indices/AnalyzeRequest.java	31.00% <0.00%> (-45.00%)	⬇️
...rch/client/transport/NoNodeAvailableException.java	28.57% <0.00%> (-42.86%)	⬇️
.../admin/cluster/reroute/ClusterRerouteResponse.java	60.00% <0.00%> (-40.00%)	⬇️
...luster/routing/allocation/RoutingExplanations.java	62.06% <0.00%> (-37.94%)	⬇️
...java/org/opensearch/threadpool/ThreadPoolInfo.java	56.25% <0.00%> (-37.50%)	⬇️
...ava/org/opensearch/search/dfs/DfsSearchResult.java	43.26% <0.00%> (-35.58%)	⬇️
...ensearch/client/indices/DetailAnalyzeResponse.java	20.54% <0.00%> (-34.25%)	⬇️
...search/search/aggregations/pipeline/EwmaModel.java	24.44% <0.00%> (-31.12%)	⬇️
... and 506 more

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