Bump Elasticsearch 8 client to 8.15.0

[cmark]

No description provided.

[nagyo]

LGTM!

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 48.46%. Comparing base (1ce13a4) to head (915849c).
Report is 7 commits behind head on 9.x.

Files	Patch %	Lines
...2international/index/es/query/Es8QueryBuilder.java	0.00%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##                9.x    #1317      +/-   ##
============================================
- Coverage     48.46%   48.46%   -0.01%     
+ Complexity    14036    14035       -1     
============================================
  Files          1949     1949              
  Lines         95377    95378       +1     
  Branches      11024    11024              
============================================
  Hits          46228    46228              
  Misses        46109    46109              
- Partials       3040     3041       +1     

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[apeteri]

👍 Do container versions also need to be updated to 8.15?

[cmark]

👍 Do container versions also need to be updated to 8.15?

I updated the one we use for testing to 8.15.0, for UAT and PROD systems we can keep using the current versions and plan to upgrade them sometime in the coming weeks.