Update settings_os_settings watch lists and OWNERS.

Now contains cr_components/chromeos and cr_elements/chromeos.

Change-Id: I99b40bf8d81e7cb3a48c8f73ac06aca570dfc904
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003148
Auto-Submit: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732249}