Revert "[TabGroupSync] Use migration + v2 flags in SavedTabGroupInteractiveTest"

This reverts commit e341f4371ec614189d88533d74efe9702c282ba1.

Reason for revert: Many builders are failing on this test. E.g.

https://ci.chromium.org/ui/p/chromium/builders/ci/mac14-arm64-rel-tests/8026/blamelist

Original change's description:
> [TabGroupSync] Use migration + v2 flags in SavedTabGroupInteractiveTest
>
> Updates SavedTabGroupInteractiveTest to use TabGroupSyncService to
> support the migration from SavedTabGroupKeyedService ->
> TabGroupSyncService.
>
> Ensures the test suite runs with and without the migration flag to
> support both code paths during the migration.
>
> Additional changes:
> - Updates the test suite to use the v2 flag by default
> - Adds a browser element identifier for the delete option in the
> tab group editor bubble view
> - Disables UnsaveGroupFromButtonMenu and EverythingButtonAlwaysShowsForV2 on Mac until after the migration
>
> Change-Id: I39bd1a4779aa9d009ab62d1c1a7dc4a547b8bc1d
> Bug: 350514491
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5870633
> Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
> Reviewed-by: Emily Shack <emshack@chromium.org>
> Commit-Queue: Darryl James <dljames@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1356790}

Bug: 350514491
Change-Id: I43bcae796554642542f0c205530c596ce1fc06b8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5869292
Owners-Override: Fergal Daly <fergal@google.com>
Commit-Queue: Fergal Daly <fergal@chromium.org>
Auto-Submit: Fergal Daly <fergal@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1356905}