Remove validation requirement for 1+ modules
Remove validation requirement for 1+ modules

It's possible to create a dashboard with no modules in the admin app,
so it should be possible here too.

keithiopia/spotlight,tijmenb/spotlight,alphagov/spotlight,alphagov/spotlight,tijmenb/spotlight,keithiopia/spotlight,tijmenb/spotlight,alphagov/spotlight,keithiopia/spotlight