sidebar: Fix behavior of "Remove Project" button (#53242)

- Fix an issue where the "remove project" button, available in the
header's ellipsis menu, wouldn't do anything if the sidebar contained
only one project
- Fix another issue where attempting to remove a project when the
sidebar has more than one project wouldn't actually remove it. This is
fixed by cleaning up the project group keys after its been already
removed.

Release Notes:

- N/A
7adbee0cdcDanilo Leal committed on 4/6/2026, 7:34:36 PM· committed by GitHubparent383b0a7
1 file changedLine totals unavailable