Move Fedora CI container defition back to global scopt

It appears to be working on the runners now, so redo this to make future
maintenance easy.

This reverts commit ebbb12f6be.

.gitlab/Fedora-Linux-CI.yml

@@ -6,7 +6,7 @@
 # Don't tag until we have separate CI for MRs
 #  tags:
 #    - kicad-fedora
-  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:40
+  image: $DEFAULT_FEDORA_IMAGE
   extends: .only_code
   interruptible: false
   cache:
@@ -144,7 +144,7 @@ fedora_report_metrics_public:
 # Run the code unit tests.
 ##########################################################################
 .fedora_qa:
-  image: registry.gitlab.com/kicad/kicad-ci/source_containers/master/fedora:40
+  image: $DEFAULT_FEDORA_IMAGE
   extends:
     - .unit_test
     - .only_code