[registration][templates] delete migration e-mail

This email was used for users migration to the supervision system.
Fixes #569
1 job for 569_cleanup_account_supervision_check_migration in 15 minutes and 33 seconds (queued for 11 seconds)
Status Job ID Name Coverage
  Build
passed #209912
docker-build
build_linux_36

00:15:33

69.0%