Add `pane: unpin all tabs` (#32423)

After integrating pinned tabs into my workflow, I've come to the
conclusion that it is painfully slow to unpin all tabs by hand.


https://github.com/user-attachments/assets/ad087b8e-4595-4c4d-827f-188e36170c25

Release Notes:

- Added a `pane: unpin all tabs` action
6d64058fc6Joseph T. Lyons committed on 6/10/2025, 12:25:22 AM· committed by GitHubparent7c2822a
1 file changedLine totals unavailable