This PR adds some clean up to the worktree picker: making sure that
worktree names render just one line, even when they might have multiple
lines (that was making each line item break for me), removing
superfluous icons, and making the footer controls more consistent with
the branch picker, where the buttons change to "Create..." if you're in
a state where the only match is the one to create a new worktree.


https://github.com/user-attachments/assets/e63aa8c9-b5a0-443d-a2ab-7759daed10d1

Release Notes:

- Git: Fixed some UI bugs in the worktree picker as well as improved the
UX for creating worktrees based off of the current or default branch.