[2.19] Update to Jackson 2.18.6

[andrross]

Check List

• Functionality includes testing.

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[github-actions]

PR Reviewer Guide 🔍

(Review updated until commit c5026c9)

Here are some key observations to aid the review process:

🧪 No relevant tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ Recommended focus areas for review SHA1 Verification The SHA1 checksums for the new Jackson 2.18.6 JARs should be verified against the official Maven Central repository to ensure the artifacts are authentic and have not been tampered with. Multiple modules share the same SHA1 for jackson-annotations and jackson-databind, which is expected, but should be confirmed. jackson = "2.18.6" jackson_databind = "2.18.6"

[github-actions]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	Add missing PR reference in changelog The changelog entry has an empty link with no PR number or URL. This should reference the actual pull request that introduced this change, similar to other entries in the changelog. CHANGELOG.md [13] -- Bump Jackson from 2.18.2 to 2.18.6 ([]()) +- Bump Jackson from 2.18.2 to 2.18.6 ([#XXXXX](https://github.com/opensearch-project/OpenSearch/pull/XXXXX)) Suggestion importance[1-10]: 6 __ Why: The changelog entry - Bump Jackson from 2.18.2 to 2.18.6 ([]()) has an empty link placeholder with no PR number or URL, unlike all other entries in the changelog. This should be filled in with the actual PR reference before merging.	Low

[github-actions]

Persistent review updated to latest commit c5026c9

[github-actions]

✅ Gradle check result for c5026c9: SUCCESS

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.95%. Comparing base (57ee1be) to head (c5026c9).
⚠️ Report is 3 commits behind head on 2.19.

Additional details and impacted files

@@             Coverage Diff              @@
##               2.19   #20813      +/-   ##
============================================
+ Coverage     71.90%   71.95%   +0.04%     
- Complexity    65964    66011      +47     
============================================
  Files          5342     5342              
  Lines        307362   307362              
  Branches      44857    44857              
============================================
+ Hits         221019   221152     +133     
+ Misses        67860    67728     -132     
+ Partials      18483    18482       -1     

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