[MsgRefactor] Remove message cards when we delete all cards

- We do not remove all message cards when we delete all tabs via the
	TabListEditor.
- This handles this case, and remove all message cards when it occurs.
- Update tests.

Bug: 440569481
Change-Id: I2a97848f5f649f9158d909f83b7bcdb1bcc70c99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6908068
Auto-Submit: Fiaz Muhammad <mfiaz@google.com>
Commit-Queue: Sky Malice <skym@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1510910}