Fix X11 display: share x11 unconditionally (drop fallback-x11)

O3DE's bundled Qt only ships the xcb platform plugin, so it needs X11/
XWayland. Using --socket=fallback-x11 alongside --socket=wayland meant X11
was not shared on Wayland sessions, leaving DISPLAY empty and Qt unable to
connect. Share --socket=x11 unconditionally instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/make-flatpak.sh

@@ -51,7 +51,6 @@ flatpak build-finish build-dir \
   --share=ipc \
   --share=network \
   --socket=x11 \
-  --socket=fallback-x11 \
   --socket=wayland \
   --socket=pulseaudio \
   --device=dri \