fix: use c10s-gnome-50-fresh COPR (fully populated with all packages)

c10s-gnome-50 is incomplete (gnome50-el10-compat and others have no builds).
c10s-gnome-50-fresh has 578 RPMs including gnome50-el10-compat, mutter,
selinux-policy-43, libadwaita, and the full GNOME 50 stack.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: James Reilly

build_scripts/overrides/base/10-packages-image-base.sh

@@ -14,7 +14,7 @@ dnf -y install 'dnf-command(versionlock)'
 
 if [[ "${GNOME_VERSION:-49}" == "50" ]]; then
     # GNOME 50 COPR
-    dnf copr enable -y "jreilly1821/c10s-gnome-50"
+    dnf copr enable -y "jreilly1821/c10s-gnome-50-fresh"
 
     # These upgrades MUST happen before the GNOME group install.
     # - glib2: EL10 ships 2.80.x; gnome-shell 50.x requires 2.84+ API symbols.