The shared Google Drive and Google Photos client_id is being retired and
will stop working during 2026. Warn users who rely on it (ie who have not
configured their own client_id) so they can create their own in advance.
The warning is only shown for auth flows that actually use the shared
client_id, not for service account, environment or anonymous auth.
See: https://forum.rclone.org/t/google-drive-and-google-photos-users-action-required/54005
Nick Craig-Wood
d03eb58586