Work towards getting isolated built-in extension compiles

For #271167

This makes it so our built-in extensions can mostly be built using `tsc` on the command line. Previously the extensions were picking up a lot of typing info from the root `node_modules` that meant they weren't truly independent

extensions/markdown-language-features/notebook/tsconfig.json

@@ -9,6 +9,11 @@
 			"ES2024",
 			"DOM",
 			"DOM.Iterable"
-		]
+		],
+		"types": [],
+		"typeRoots": [
+			"../node_modules/@types"
+		],
+		"skipLibCheck": true
 	}
 }