[Tab Groups] Add regression test for an AppMenu tab duplication bug

Adds a regression test to guard against future changes that could
reintroduce a bug where hovering between 2 different tab groups in the
tab groups sub menu would cause the tabs to duplicate.

Clicking on the wrong entries would then cause the browser to crash
because the backing tab model has been removed.

The added tests does the exact repro that was previously causing the
bug.

Change-Id: I9debfc8d1f3ebf8d8480329e2f9019f835dd5799
Bug: 415793647
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6549075
Reviewed-by: Eshwar Stalin <estalin@chromium.org>
Commit-Queue: Darryl James <dljames@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1461020}