Removing metrics which are not required now as were removed in OS 2.0

[sgup432]

Signed-off-by: Sagar Upadhyaya sagar.upadhyaya.121@gmail.com

Is your feature request related to a problem? Please provide an existing Issue # , or describe.
Removing segment related memory metrics as they were removed from OS 2.0 here - opensearch-project/OpenSearch@fc0d3a3.

We had removed references of these in PA as well earlier.

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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

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[codecov-commenter]

Codecov Report

Merging #159 (5c19cec) into main (99d6d42) will decrease coverage by 0.04%.
The diff coverage is n/a.

❗ Current head 5c19cec differs from pull request most recent head 5e4eb15. Consider uploading reports for the commit 5e4eb15 to get more accurate results

@@             Coverage Diff              @@
##               main     #159      +/-   ##
============================================
- Coverage     71.93%   71.89%   -0.05%     
- Complexity     2949     2951       +2     
============================================
  Files           376      376              
  Lines         18782    18747      -35     
  Branches       1442     1442              
============================================
- Hits          13511    13478      -33     
  Misses         4675     4675              
+ Partials        596      594       -2     

Impacted Files	Coverage Δ
...opensearch/performanceanalyzer/jvm/ThreadList.java	12.34% <ø> (ø)
...search/performanceanalyzer/metrics/AllMetrics.java	86.47% <ø> (-0.16%)	⬇️
...search/performanceanalyzer/model/MetricsModel.java	100.00% <ø> (ø)
...nceanalyzer/rca/store/OpenSearchAnalysisGraph.java	100.00% <ø> (ø)
...performanceanalyzer/collectors/StatsCollector.java	93.23% <0.00%> (+0.75%)	⬆️
...nalyzer/rca/net/handler/PublishRequestHandler.java	87.75% <0.00%> (+2.04%)	⬆️

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[sruti1312]

Documentation needs to be updated that these metrics are not supported.
https://opendistro.github.io/for-elasticsearch-docs/docs/pa/reference/