Add enterprise policy for new smart content grouping features

Create a new policy to disable smart content grouping features on Chrome
OS and also implement the usage.

birch_coral_provider: Suppress the data loading if the policy doesn't
allow.

birch_bar_context_menu_model: Disable the coral option if the policy
doesn't allow.

birch_chip_context_menu_model: Do not show the user feedback item if the
policy doesn't allow.

tab_app_selection_view: Do not show user feedback view containing the
thumbs up/down icon if the policy doesn't allow.

Test: manual through go/using-yaps
Bug: 364708972
Change-Id: Ie7ca4d456624bb46d01973195a5cec681547067e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6171515
Commit-Queue: Xiaodan Zhu <zxdan@chromium.org>
Reviewed-by: Howard Yang <hcyang@google.com>
Reviewed-by: Xiaodan Zhu <zxdan@chromium.org>
Auto-Submit: Hsu-Cheng Tsai <hctsai@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1423968}