[Autofill Auth UI] Merge MVCs of VerifyPendingDialog and WebauthnOfferDialog

The verify pending dialog will need to (UX decision) reuse the current
webauthn dialog UX format. Since they are both using this format, and
are for the same flow. It makes sense to merge the two sets of MVCs and
show different content based on different dialog state

This is a follow up of CL crrev.com/c/1925761

Bug: 991037
Change-Id: I4837e02adeef471d6a775587af0ab921646cdaf5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1931857
Commit-Queue: Siyu An <siyua@chromium.org>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: Jared Saul <jsaul@google.com>
Reviewed-by: Fabio Tirelo <ftirelo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720817}
31 files changed