Use uniform color for protected/default branches/tags (#439551)

What does this MR do and why?

This MR uses a uniform color, info. (blue) for default branch and neutral (gray) for protected branches and tags.

See #439551 (closed)

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After
Code > Branches
Code > Tags
Branch Selector (dropdown)	No change
Settings > Branch Selector

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

/cc @mle