branch_picker: Add button to filter remote branches (#54632)

This PR brings back the button to filter remote branches when accessing
the title bar's branch picker with the mouse. It was unintentionally
removed when we introduced the new worktree picker.

Release Notes:

- N/A
0ab64d6414Danilo Leal committed on 4/23/2026, 6:26:44 PM· committed by GitHubparent398f430
64 files changedLine totals unavailable