snap-groups: Verify and rename SkipFormSnapGroupAfterSnapping

This modifies the test to verify the user action. Also snuck in some
other user actions.

Test: modified
Bug: b/344987163
Change-Id: I773fac1fabb2a80416c81cc2223b6cf4a5a2d7e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5599718


Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Michele Fan <michelefan@chromium.org>
Commit-Queue: Sophie Wen <sophiewen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1312175}