Fix flaky SyncConsentFragmentTest#testManagedAccount*

Flakiness caused by espresso 3.2. Need to look for the view in the
dialog's root.

Bug: 330570364
Change-Id: Ifdff3b7bc8c8f9aac54e15c0e92c7f4129b288d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5383936


Auto-Submit: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1276834}