Ignore auth errors from non-sync accounts

sync_ui_util displays a sync error even for Secondary Accounts, which
are not being used as the Sync Account. This can happen if
SigninErrorController is running in |AccountMode::ANY_ACCOUNT|, e.g. on
Chrome OS.

Fix this by specifically checking the error state of the Sync Account
instead of using errors from any account.

Bug: 971475
Test: unit_tests --gtest_filter="*SyncUIUtilTest*"
Change-Id: I871257cef082c4cee7fd1be5f84d1c2f50441422
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1648217
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Kush Sinha <sinhak@chromium.org>
Commit-Queue: Kush Sinha <sinhak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667146}
2 files changed