[Mahi] Remove the disclaimer view from chrome/browser

The disclaimer view was added under ash. Now using the one under ash
instead.

Bug: b/341832244
Change-Id: I1adab326968362ae7e5e8267c570ce43588e5ac5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5618993


Commit-Queue: Jiaming Cheng <jiamingc@chromium.org>
Reviewed-by: Andre Le <leandre@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313719}