This commit removes create_web_public_stream_policy setting
since web-public channel creation permissions are now
handled by group-based setting.
We still pass "realm_create_web_public_stream_policy" in
"/register" response though for older clients with its
value being set depending on the value of group based
setting. If we cannot set its value to an appropriate enum
corresponding to the group setting, then we set it to
"Admins and moderators" considering that server will not
allow the users without permissions to create web-public
channels but the client can make sure that UI is
available to the users who have permission.
6919448917