Add test for `pane: toggle pin tab` (#31906)

Also adds the optimization to not move a tab being pinned when its
destination index is the same as its index.

Release Notes:

- N/A
1ed4647203Joseph T. Lyons committed on 6/2/2025, 3:58:10 PM· committed by GitHubparentebed567
1 file changedLine totals unavailable