Merge pull request #31033 from LumiGuide/fix-clementine-m4a

clementine: Added gst-libav plugin

pkgs/top-level/all-packages.nix

···
   clementine = callPackage ../applications/audio/clementine {
     boost = boost155;
     gst_plugins =
-      with gst_all_1; [ gst-plugins-base gst-plugins-good gst-plugins-ugly ];
+      with gst_all_1; [ gst-plugins-base gst-plugins-good gst-plugins-ugly gst-libav ];
   };
 
   clementineFree = clementine.free;