Update docker.elastic.co/elasticsearch/elasticsearch Docker tag to v8.15.3

[renovate[bot]]

This PR contains the following updates:

Package	Update	Change
docker.elastic.co/elasticsearch/elasticsearch (source)	patch	8.15.2 -> 8.15.3

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Release Notes

elastic/elasticsearch (docker.elastic.co/elasticsearch/elasticsearch)

### [`v8.15.3`](https://redirect.github.com/elastic/elasticsearch/releases/tag/v8.15.3): Elasticsearch 8.15.3 [Compare Source](https://redirect.github.com/elastic/elasticsearch/compare/v8.15.2...v8.15.3) Downloads: https://elastic.co/downloads/elasticsearch Release notes: https://www.elastic.co/guide/en/elasticsearch/reference/8.15/release-notes-8.15.3.html

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