Date Histogram Optimization with Date Rounding utility refactoring (#19088)

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Signed-off-by: Sandesh Kumar <sandeshkr419@gmail.com>

Author: sandeshkr419

CHANGELOG.md

@@ -35,6 +35,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Disable pruning for `doc_values` for the wildcard field mapper ([#18568](https://github.com/opensearch-project/OpenSearch/pull/18568))
 - Make all methods in Engine.Result public ([#19276](https://github.com/opensearch-project/OpenSearch/pull/19275))
 - Create and attach interclusterTest and yamlRestTest code coverage reports to gradle check task([#19165](https://github.com/opensearch-project/OpenSearch/pull/19165))
+- Optimized date histogram aggregations by preventing unnecessary object allocations in date rounding utils ([19088](https://github.com/opensearch-project/OpenSearch/pull/19088))
 
 ### Fixed
 - Fix unnecessary refreshes on update preparation failures ([#15261](https://github.com/opensearch-project/OpenSearch/issues/15261))