Fix display output in logs
Fix display output in logs

Background:
https://github.com/roots/trellis/pull/1235#issuecomment-729621213

Ansible bases the log level based on colour (yeah, it's dumb) when
logging is enabled. `bright gray` was a valid log level mapping.

Instead of trying to pick some other colur supported in both contexts,
we can just set `screen_only` to skip these messages which are meant for
STDOUT anyway.

newtonne/trellis,roots/trellis,roots/trellis,roots/bedrock-ansible,newtonne/trellis,newtonne/trellis,roots/bedrock-ansible,pressbooks/trellis,pressbooks/trellis