[8.12] [DOCS] Backport whats new 8.12 (elastic#175030) (elastic#175042)

# Backport

This will backport the following commits from `main` to `8.12`:
- [[DOCS] Backport whats new 8.12
(elastic#175030)](elastic#175030)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Backport whats new 8.12 (elastic#175030)\n\nIncorrectly labelled the original
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backport:skip when the page needs to be\r\nbackported to 8.12. Backport
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Backport whats new 8.12 (elastic#175030)\n\nIncorrectly labelled the original
What's New page PR for 8.12. Didn't\r\ntarget 8.12 and incorrectly used
backport:skip when the page needs to be\r\nbackported to 8.12. Backport
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