Add views for the PaymentsWindowUserConsentDialog

This CL adds the view implementation and creation for the
PaymentsWindowUserConsentDialog, as well as its corresponding browser
tests. This dialog will be triggered to get user consent for initiating
a payments window flow, for which we currently only have VCN 3DS.

Mock: https://screenshot.googleplex.com/3CBZNUJ7hvNyBn9

Implementation: https://screenshot.googleplex.com/3qFCx7yRXKGJbRy

Bug: 1517762
Change-Id: I1fa422faa33ce68f257973347def9cce3f456d2b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5338589


Commit-Queue: Vinny Persky <vinnypersky@google.com>
Reviewed-by: Siyu An <siyua@chromium.org>
Reviewed-by: Dana Fried <dfried@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1280290}