Remove edit token from conflict detection

The edit conflict detection in OAuth's approval form used an edit token
generated with getEditToken(). Since
Ic4cf148cc1fa9d0561aac0bd2d68a09c7851896d a different token is returned
on each call, so the OAuth conflict detection always fails.

Since we check for CSRF on the form already, we just use the user's id
to check for edit conflicts.

Bug: 72634
Change-Id: I10b9b63936b63a83321333307577ef952d5b1078