[Backport 2.x] Fix grammar in log warnings.

[opensearch-trigger-bot[bot]]

Backport 0e3e57c2d6a83f63e00c6cb6abf94ce1d6963bed from #2928.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.49%. Comparing base (69bacd1) to head (cf8d244). Report is 1 commits behind head on 2.x.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## 2.x #3088 +/- ## ========================================= Coverage 94.49% 94.49% Complexity 5421 5421 ========================================= Files 529 529 Lines 15462 15462 Branches 1010 1010 ========================================= Hits 14611 14611 Misses 804 804 Partials 47 47 ``` | [Flag](https://app.codecov.io/gh/opensearch-project/sql/pull/3088/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project) | Coverage Δ | | |---|---|---| | [sql-engine](https://app.codecov.io/gh/opensearch-project/sql/pull/3088/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project) | `94.49% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=opensearch-project#carryforward-flags-in-the-pull-request-comment) to find out more.

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