bug: User profile errors on user creation

[bmtcril]

When a new user registers in the LMS, sometimes the user profile sink gets triggered before their user profile row is written to MySQL, likely due to the transaction not being committed, causing "UserProfile does not exist" errors in the event sink job. In these cases the user does not appear in ClickHouse until they update their profile or the management command is written.

We should either see if we can run this sink on_commit instead of on_save or put in a retry delay for these jobs.