Make projects dropdown style in new navigation consistent

What does this MR do?

Change the projects dropdowns of the new navigation to new style.

Screenshots

Before	After

What are the relevant issue numbers?

#28921 (moved), #35424 (closed)

mentioned in issue #28921 (moved)

changed the description

@cperessini Could you please take a look? Note that we have separate mouse and keyboard navigation here as well (as in !13116 (merged)).

assigned to @cperessini

added 291 commits

• f4b2ea4c...1782aa70 - 290 commits from branch master
• c4686285 - Make projects dropdown style in new navigation consistent

Compare with previous version

@winh LGTM

@annabeldunstone Can you please review?

assigned to @annabeldunstone

resolved all discussions

I was about to mention in one of your other MRs that the new nav project switcher was still using the old style . LGTM!

approved this merge request

merged

mentioned in commit 290045ad