Remove unneeded permissions

The Flatpak Command Reference suggests using both x11 and fallback-x11:

The fallback-x11 option makes the X11 socket available only if there is no Wayland socket. This option was introduced in 0.11.3. To support older Flatpak releases, specify both x11 and fallback-x11. The fallback-x11 option takes precedence when both are supported.

Hardening Flatpak Permissions Over Time says --talk-name=org.freedesktop.Notifications and dconf permissions are not needed.