Run e2e:package-and-test-ee for MR targeting stable branches

What does this MR do and why?

Run e2e:package-and-test-ee for merge requests targeting stable branches

Even before any approvals. This is a follow up from !157337 (merged) where it moved it completely after approval (tier 3)

Context: !159794 (comment 2006345736)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.