[CrOS] Don't allow revoking refresh token for supervised users.

Add logging when token revoke is requested: update token, sign out.
Don't allow revoking token in case of sign out.
Token update flow is not affected.

BUG=332032

Review URL: https://codereview.chromium.org/181113006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254193 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254193