ci: Run nightly job even if cross environment stage fails

Currently, the nightly job is skipped if fedora rawhide, or flatpak
master job fails. This is not wanted as the nightly should be published
if flatpak devel job succeeds. Let's allow failures of those jobs to
not block the deploy stage.
2 jobs for wip/oholy/ci-improvements in 10 minutes and 18 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #672199
flatpak
flatpak devel

00:10:18

passed #672200
style check

00:02:20