[TabGroupIndicators] Clear drag when group delete dialog is showing

- Show dialog when last tab in group is being dragged off tab strip.
- Clear drag when dialog is showing.
- Only delete tab group when the last tab in group is dropped in a valid place and the drop is handled(tab reparented), otherwise restore tab group back to original position.

Show dialog behavior: https://drive.google.com/file/d/17XYMB9ha82nguUfzJJ2hc5Mh1mf2GdX7/view?usp=sharing

Skip dialog behavior: https://drive.google.com/file/d/17VA6aP9Xro3pwY9JrKdHiHGNoUGyCXF9/view?usp=sharing

Bug: 340940928, 348045086
Change-Id: I8c69a67b7708a4d585010456a4399e0c66a0ca7f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5661017
Commit-Queue: Zhe Li <zheliooo@google.com>
Reviewed-by: Neil Coronado <nemco@google.com>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1324337}