chg: ci: Do not question obvious human Co-Authored-By trailers

Danger asks the reviewer to confirm that the person named in every
`Co-Authored-By` trailer is a human.  A trailer which gives a name, a
surname and an @isc.org address leaves no room for doubt, so stop
emitting that message for those and keep it for everything else.

Assisted-by: Claude:claude-opus-5[1m]
Merge branch 'mnowak/danger-human-coauthored-by' into 'main'

See merge request isc-projects/bind9!12473