CI/Flatpak: Disable Wayland by default

Author: stenzek

scripts/flatpak/org.duckstation.DuckStation.json

@@ -12,10 +12,10 @@
     "--allow=bluetooth",
     "--share=network",
     "--share=ipc",
-    "--socket=fallback-x11",
-    "--socket=wayland",
+    "--socket=x11",
     "--socket=pulseaudio",
-    "--talk-name=org.freedesktop.ScreenSaver"
+    "--talk-name=org.freedesktop.ScreenSaver",
+    "--env=QT_QPA_PLATFORM=xcb"
   ],
   "modules": [
     "modules/20-sdl2.json",