build/linux: Remove redundant plugs: in favor of 'gnome' Snap extension

See: https://documentation.ubuntu.com/snapcraft/stable/reference/extensions/gnome-extension/
(cherry picked from commit b960be9735)

build/linux/snap/snapcraft.yaml

@@ -47,10 +47,6 @@ apps:
       - home
       - network
       - removable-media
-      - desktop
-      - desktop-legacy
-      - wayland
-      - unity7
     extensions: [gnome]
 
 layout:
@@ -68,12 +64,6 @@ slots:
     bus: session
     name: org.gimp.GIMP.UI
 
-plugs:
-  gnome-46-2404:
-    interface: content
-    target: $SNAP/gnome-platform
-    default-provider: gnome-46-2404
-
 parts:
   buildenv:
     plugin: nil