Updater: ksinstall --uninstall should only uninstall the bundle.

This mitigates the risk of losing the Keystone ticket store.

Fixed: 1413816
Change-Id: I1f190fb9054ba7bc009be8aac15cbaf9fe073791
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4226043


Auto-Submit: Joshua Pawlicki <waffles@chromium.org>
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Xiaoling Bao <xiaolingbao@chromium.org>
Reviewed-by: Xiaoling Bao <xiaolingbao@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1102447}