Fix the debian:testing_release build
This broke when I changed the build to run on the x86_64 image but forgot to change the PATH for gdk-pixbuf-query-loaders, see commit c5f09c73.
This only affects the scheduled pipeline. I checked that this change actually fixes it, see https://gitlab.gnome.org/svenfoo/librsvg/-/pipelines/218825
Edited by Sven Neumann