toytoolkit: don't ignore resizes with negative width or height

E.g. this can happen when you grab the lower right corner of a window
and move over the top of the window when resizing. In this case, the
changed width is still important and should be acted upon.

https://bugs.freedesktop.org/show_bug.cgi?id=53560

clients/window.c

@@ -2691,9 +2691,6 @@ handle_configure(void *data, struct wl_shell_surface *shell_surface,
 {
 	struct window *window = data;
 
-	if (width <= 0 || height <= 0)
-		return;
-
 	window->resize_edges = edges;
 	window_schedule_resize(window, width, height);
 }