Change `groupByValue` to use values not 'channel'
Change `groupByValue` to use values not 'channel'

- Before we were hard coding 'channel' as the group_by value

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