[Signin][Android] Make FRE landscape welcome page scrollable and fix ToS to...

[Signin][Android] Make FRE landscape welcome page scrollable and fix ToS to the bottom of the screen.

Fixed: 1444428
Change-Id: I1149e7252be40c79efef051eadbab4e985b8e562
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4525339


Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Samar Chehade-Lepleux <samarchehade@google.com>
Cr-Commit-Position: refs/heads/main@{#1148385}