Fix old nav pipelines and add selectors to new sidebar shortcuts

What does this MR do and why?

Adds disable_new_navigation since the new sidebar is now enabled by default.

Fixes E2E Omnibus Old Navigation pipeline (Example failure) which fails because the new sidebar is enabled when it shouldn't be.

Also adds data-testids to the issue and merge request shortcuts in the new sidebar.

This should fix about 20 failure issues.

MR acceptance checklist

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