[8.15](backport #40643) bump: ubi 9.4 for docker arm ubi images

[mergify]

Proposed commit message

Bump the version to 9.4 for arm docker images

while it's 9.4 for x86:

docker inspect docker.elastic.co/ubi9/ubi-minimal | grep version
                "io.buildah.version": "1.29.0",
                "version": "9.4"

#40633 will be caring of maintaining these set of changes too

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

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This is an automatic backport of pull request #40643 done by [Mergify](https://mergify.com).

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