ci: Remove .build-linux from Hurd CI scheduled job

It’s intended to be used with Linux Docker images, and it assumes a certain filesystem layout of the image being run (in particular, that it has a $HOME/subprojects directory pre-populated with the subprojects for glib.git). That’s not the case for Hurd, which is running on a dedicated runner (not using Docker), so drop this include.

This should fix the CI failure here: https://gitlab.gnome.org/GNOME/glib/-/jobs/3223275

Signed-off-by: Philip Withnall philip@tecnocode.co.uk