Revert "Implement Mandatory Reauth confirmation bubble."

This reverts commit 743cf6dc.

Reason for revert: Failing undefined behavior sanitizer

Failure build: https://ci.chromium.org/ui/p/chromium/builders/ci/linux-ubsan-vptr/23235/overview

Original change's description:
> Implement Mandatory Reauth confirmation bubble.
>
> This bubble is displayed after the user has agreed to enable Mandatory
> Reauth.
>
> Screenshot:
> https://screenshot.googleplex.com/A4Qvsi5r3s3THyD.png
>
> Mockup:
> https://screenshot.googleplex.com/4kPoTf8owipR3vL.png
>
> Bug: 1427216
> Change-Id: I5e2d32596ba08a2cc66e2f6bd1a594fbac91b90c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4499402


> Commit-Queue: Justin Wells <justinleewells@google.com>
> Reviewed-by: Vinny Persky <vinnypersky@google.com>
> Cr-Commit-Position: refs/heads/main@{#1148009}

Bug: 1427216
Change-Id: Ia169bd5a289df995093214fc6b6cbbca906bbcb6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4560384


Reviewed-by: Vinny Persky <vinnypersky@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Jiewei Qian <qjw@chromium.org>
Commit-Queue: Jiewei Qian <qjw@chromium.org>
Reviewed-by: Jiewei Qian <qjw@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1148282}