Try cleaning/expecting clean user state in the system tests.

Bug: 345276604
Change-Id: I8ed3bd00ececf6a840b3d3d02f3299e0857c4de6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5599073


Commit-Queue: Adam Norberg <norberg@google.com>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Reviewed-by: Xiaoling Bao <xiaolingbao@chromium.org>
Reviewed-by: Sorin Jianu <sorin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313097}