Fix #4023: background mismatch for latex previews

A doom-load-theme-hook hook fixes the background of latex previews, but
by the time org is loaded, this hook will have long since triggered,
giving it no change to update its background, so we must run it at least
once, immediately.

modules/lang/org/config.el

@@ -142,6 +142,7 @@ This forces it to read the background before rendering."
                                         remap)
                                       'default)
                                   :background nil t))))
+  (+org-refresh-latex-background-h)
 
   ;; HACK Face specs fed directly to `org-todo-keyword-faces' don't respect
   ;;      underlying faces like the `org-todo' face does, so we define our own