[UNOp2][Android] Suppress history sync when it is declined often.

We also clean up usages of `addAccount(email)` in
SigninAndHistoryOptInIntegrationTest.

Fixed: 331568233
Change-Id: Id790cd3e9cbae8bd0d91e0dd5ef4363baa5df187
Bug: 40890215
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5594216


Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Samar Chehade-Lepleux <samarchehade@google.com>
Reviewed-by: Menghan Yang <myuu@google.com>
Cr-Commit-Position: refs/heads/main@{#1312832}