wayland: Always trigger a resize when handling a configure event.

When we removed the OpenGL resize workaround it introduced a problem for
fullscreen windows in particular: When leaving fullscreen we tried to send a
resize event, but UpdateFullscreenMode would send a SIZE_CHANGED immediately
after, deleting our resize event and causing the following configure event's
resize to be ignored. This timing issue resulted in fullscreen windows not
being resized at all when becoming a floating window.

By always forcing resize events from configure events, we ensure that RESIZED
always makes it through. SetWindowSize-type changes should be unaffected as
they do not fire configure events.

src/video/wayland/SDL_waylandwindow.c

@@ -1219,7 +1219,7 @@ Wayland_HandlePendingResize(SDL_Window *window)
 
     if (data->resize.pending) {
         struct wl_region *region;
-        if (data->scale_factor != data->resize.scale_factor) {
+        if (data->scale_factor != data->resize.scale_factor || data->resize.configure) {
             window->w = 0;
             window->h = 0;
         }