[TabGroupIndicators] Update bottom outline width in edge case

Update bottom outline width in edge case.
-If a tab moves in/out of a group without changing index, we won't
 rebuild the strip views (and the bottom outline). In that case,
 manually update the bottom outline.

Bug: 331864413
Change-Id: I730b18b44ebeb1a8aeb8c808e1ccea145b052502
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5405909
Commit-Queue: Neil Coronado <nemco@google.com>
Reviewed-by: Zhe Li <zheliooo@google.com>
Cr-Commit-Position: refs/heads/main@{#1280298}