[Vertical Tabs] Use StripDragShadowView for external drag shadows

Adopt StripDragShadowView in Vertical Tabs during external drag of tabs
and tab groups to align the drag shadow visuals with the horizontal tab
strip.

* Adopt StripDragShadowView and MultiThumbnailCardProvider in
  VerticalTabListCoordinator for external tab and group drags.
* Decouple StripDragShadowView from LayerTitleCache by supporting a
  nullable supplier with direct tab model title and favicon fallbacks.
* Add refreshDragShadow in TabSwitcherDragHandler to handle async
  thumbnail and favicon updates.
* Pass BrowserControlsStateProvider to VerticalTabListCoordinator for
  card sizing calculations.
* Add and update unit tests for StripDragShadowView and drag initiation.

Demo: https://screencast.googleplex.com/cast/NDgyNDMwMDI4NzY4ODcwNHxkMjQ3MTJhMS1jNg

Bug: 553090178
Change-Id: I7c47b242e3ca7c62356d1f8e03355af60914a72f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8300234
Reviewed-by: Neil Coronado <nemco@google.com>
Reviewed-by: Jack Thiesen <jthiesen@chromium.org>
Commit-Queue: Gazal Agarwal <agazal@google.com>
Auto-Submit: Gazal Agarwal <agazal@google.com>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Reviewed-by: Zhe Li <zheliooo@google.com>
Cr-Commit-Position: refs/heads/main@{#1688451}