libobs: Fix bug where cropped items would recalc transform

Fixes a bug where items that had cropping would recalculate transform
every frame.  obs_scene_item::last_width and obs_scene_item::last_height
would be set to the cropped sizes rather than the source's actual size.

libobs/obs-scene.c

@@ -323,6 +323,9 @@ static void update_item_transform(struct obs_scene_item *item)
 	if (os_atomic_load_long(&item->defer_update) > 0)
 		return;
 
+	item->last_width  = width;
+	item->last_height = height;
+
 	width = cx;
 	height = cy;
 
@@ -375,9 +378,6 @@ static void update_item_transform(struct obs_scene_item *item)
 
 	/* ----------------------- */
 
-	item->last_width  = width;
-	item->last_height = height;
-
 	calldata_init_fixed(&params, stack, sizeof(stack));
 	calldata_set_ptr(&params, "scene", item->parent);
 	calldata_set_ptr(&params, "item", item);