Upgrade New MR Page Tabs to use Pajamas Rails Helper for Tabs

What does this MR do and why?

For #230769.

MR	Description
!81502 (merged)	In preparation for swapping the New MR page to use Pajamas Tabs, we're extracting some of the code from the old class to shareable functions
We're here! 👉🏻	This MR swaps the behavior code from the old Bootstrap implementation to the structure needed to support the Pajamas Tabs component

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