Set default to native resolution of display if Steam tries to force 7…

…20p/800p

You can select 720p/800p still in game or via Steam's resolution setting
Steam > Settings > Display > Resolution

This effectively reverts the changes Valve made a year ago forcing us to
720p.

src/steamcompmgr.cpp

@@ -4959,6 +4959,13 @@ handle_property_notify(xwayland_ctx_t *ctx, XPropertyEvent *ev)
 			size_t server_idx = size_t{ xwayland_mode_ctl[ 0 ] };
 			int width = xwayland_mode_ctl[ 1 ];
 			int height = xwayland_mode_ctl[ 2 ];
+
+			if ( g_nOutputWidth != 1280 && width == 1280 )
+			{
+				width = g_nOutputWidth;
+				height = g_nOutputHeight;
+			}
+
 			bool allowSuperRes = !!xwayland_mode_ctl[ 3 ];
 
 			if ( !allowSuperRes )