[Backport 2.x] Add mac platform to CI

[opensearch-trigger-bot]

Backport 5bb7a3f from #590

[codecov-commenter]

Codecov Report

Merging #591 (5bb7a3f) into 2.x (ba023ec) will increase coverage by 0.75%.
The diff coverage is 85.85%.

❗ Current head 5bb7a3f differs from pull request most recent head 66a1120. Consider uploading reports for the commit 66a1120 to get more accurate results

@@             Coverage Diff              @@
##                2.x     #591      +/-   ##
============================================
+ Coverage     84.01%   84.77%   +0.75%     
- Complexity     1032     1059      +27     
============================================
  Files           148      149       +1     
  Lines          4222     4301      +79     
  Branches        373      382       +9     
============================================
+ Hits           3547     3646      +99     
+ Misses          499      480      -19     
+ Partials        176      175       -1     

Impacted Files	Coverage Δ
...n/java/org/opensearch/knn/common/KNNConstants.java	93.33% <ø> (ø)
.../main/java/org/opensearch/knn/index/IndexUtil.java	55.73% <ø> (ø)
...va/org/opensearch/knn/index/KNNCircuitBreaker.java	80.00% <0.00%> (+20.00%)	⬆️
.../main/java/org/opensearch/knn/index/KNNMethod.java	100.00% <ø> (ø)
...ava/org/opensearch/knn/index/KNNMethodContext.java	92.50% <ø> (ø)
...java/org/opensearch/knn/index/MethodComponent.java	88.88% <ø> (ø)
...g/opensearch/knn/index/MethodComponentContext.java	91.13% <ø> (ø)
...earch/knn/index/memory/NativeMemoryAllocation.java	82.92% <ø> (ø)
.../java/org/opensearch/knn/index/query/KNNQuery.java	83.33% <ø> (ø)
...org/opensearch/knn/index/query/KNNQueryResult.java	100.00% <ø> (ø)
... and 85 more

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