Warn users that the protected branch hasn't been merged before deletion
Description
Add a conditional warning to the Delete protected branch modal if the branch hasn't been merged yet.
Originally proposed in #21393 (closed), which redesigned the “Delete protected branch” modal, but ended up not being implemented in !11000 (merged). This warning is also part of #28849 (closed), a larger initiative to redesign confirmation modals throughout GitLab.
Proposal
This branch hasn’t been merged yet. To avoid data loss, consider merging this branch into another before deleting it.
Links / references
- Originally proposed in #21393 (closed)