Revert "Remove the fallback AddSupervisedUserActivity."

This reverts commit 86f350043905987fe950e1c197e1b27a8d9b73e5.

Reason for revert: Real flow is not ready yet, so we still need the fallback activity.

Change-Id: I34dc5386ff8c18a62b4b11e25fd355a62602329f
5 files changed