gpui: Add tab group (#38531)

Closes #ISSUE

Co-Authored-By: Mikayla <mikayla@zed.dev>
Co-Authored-By: Anthony <anthony@zed.dev>
Co-Authored-By: Kate <kate@zed.dev>

Release Notes:

- N/A *or* Added/Fixed/Improved ...

---------

Co-authored-by: Kate <kate@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Anthony <anthony@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>

Cargo.lock

@@ -7087,6 +7087,7 @@ dependencies = [
  "parking_lot",
  "pathfinder_geometry",
  "postage",
+ "pretty_assertions",
  "profiling",
  "rand 0.9.1",
  "raw-window-handle",