nixos/sway: workaround idle inhibit not working

in Firefox

Source:
https://www.reddit.com/r/swaywm/comments/1dqud2a/how_to_get_firefox_to_inhibit_idle_when_watching/
> Firefox supports the Wayaland inhibit protocol, but it attempts to use the DBus interfaces first. However, the gtk portal has an issue where it returns success even though the wlr portal/sway doesn't have an implementation for the inhibit method, see #465.

nixos/modules/programs/wayland/sway.nix

@@ -144,7 +144,19 @@ in
       services.displayManager.sessionPackages = lib.optional (cfg.package != null) cfg.package;
 
       # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1050913
-      xdg.portal.config.sway.default = lib.mkDefault [ "wlr" "gtk" ];
+      # https://github.com/emersion/xdg-desktop-portal-wlr/blob/master/contrib/wlroots-portals.conf
+      # https://github.com/emersion/xdg-desktop-portal-wlr/pull/315
+      xdg.portal.config.sway = {
+        # Use xdg-desktop-portal-gtk for every portal interface...
+        default = "gtk";
+        # ... except for the ScreenCast, Screenshot and Secret
+        "org.freedesktop.impl.portal.ScreenCast" = "wlr";
+        "org.freedesktop.impl.portal.Screenshot" = "wlr";
+        # ignore inhibit bc gtk portal always returns as success,
+        # despite sway/the wlr portal not having an implementation,
+        # stopping firefox from using wayland idle-inhibit
+        "org.freedesktop.impl.portal.Inhibit" = "none";
+      };
     }
 
     (import ./wayland-session.nix {