toast: Update padding for toast with buttons and add a new ctor

Added a 2dp padding on the right side of the toast button to account for
the focus ring halo and to match specs. Updated pixel tests to match.

Also, added a constructor that receives the specific elements needed to
build a SystemToastView, instead of just accepting ToastData as a
parameter, since that requires an id and a catalog names, but not all
toast views need to be created through the manager (e.g. FasterSplitView
and ScreenCapture toast view).

Bug: b:322363990
Change-Id: I0fc0010a5ef58122e506b3002261ee103eb8ee9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5468580
Reviewed-by: Jiaming Cheng <jiamingc@chromium.org>
Commit-Queue: Kevin Radtke <kradtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1292097}