Disable the checks for PO files

You can revert this commit once the CI environment has a recent enough
gettext version.
6 jobs for 178-purge-the-useless-code in 70 minutes and 5 seconds (queued for 1 second)
Status Job ID Name Coverage
  Dist
passed #649124
dist

00:40:41

 
  Check
passed #649125
check

00:04:20

passed #649127
deb

00:09:40

passed #649126
mingw

00:24:05

 
  Manual
passed #649128
pages

00:05:18

 
  Deploy
passed pages:deploy

00:00:02