[Vertical Tabs] Scroll-in animating tabs in the non-overflow state

This CL handles the sepecific edge case where:
  - Animating view is activated
  - ScrollView is in a non-overflow state
  - Final animated bounds are partially overflowing

This is handled by a follow-up call to
EnsureVisibleInViewportPostActivationAndLayout() which will scroll-in
the view (if necessary).

Bug: 485334280, 459824840
Change-Id: I84e91b4377915b0695bfe6e7360c34a0c8728c95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7651216
Commit-Queue: Tom Lukaszewicz <tluk@chromium.org>
Reviewed-by: Eshwar Stalin <estalin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1599630}