[TabGroupIndicators] Add dialog when closing last tab in group

- Adding back the "close from group" strings and ActionConfirmationManager#processCloseTabAttempt that were removed previously use to no usage.
- Hook up remove last tab from group dialog in StripLayoutHelper#handleCloseButtonClick

demo: https://drive.google.com/file/d/1AuT1eT3bIlvU7BwUDYSfZWyBftu5fl8o/view?usp=sharing

TODO: Follow up with UX on a spec for closing the last tab in a group on the tab strip. Currently, we are just temporarily hiding the group, same as the behavior when dragging the last tab out of the group.

Bug: 348045806
Change-Id: Ib89fd4081daf3076ffd3bb1d842ac971f1e69d4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5717301
Commit-Queue: Zhe Li <zheliooo@google.com>
Reviewed-by: Sirisha Kavuluru <skavuluru@google.com>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1331293}