[ticket/12342] Fix the Custom Dates function in UCP Prefs Global

Function was being called before dE() function exists,
causing it to fail. Should be called when the page/window
is ready.

PHPBB3-12342

phpBB/styles/prosilver/template/ucp_prefs_personal.html

@@ -117,7 +117,7 @@
 		}
 	}
 
-	customDates();
+	window.onload = customDates;
 // ]]>
 </script>