load iife version of msw

src/Umbraco.Web.UI.Client/index.html

@@ -5,6 +5,7 @@
 		<link rel="icon" type="image/svg+xml" href="favicon.svg" />
 		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
 		<title>Umbraco</title>
+		<script src="/node_modules/msw/lib/iife/index.js"></script>
 		<script type="module" src="/src/index.ts"></script>
 		<base href="/" />
 	</head>