Fixed overlap of merge request tabs

What does this MR do and why?

Fixes the merge request tabs overlapping when scrolling down the page

Screenshots or screen recordings

Screen_Recording_2022-10-10_at_10.56.43

How to set up and validate locally

1. Visit merge request
2. Scroll down page until the tabs stick

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.