tsconfig-ext: revert bc52f65b26

While the intent was to run tests with it, we don't need it. Instead,
this caused problems because the stubs overrode the intended `ext`
directory and therefore disabled the ext features.

tsconfig-ext.json

@@ -3,9 +3,6 @@
   "files": [],
   "include": [],
   "references": [
-    { "path": "./app" },
-    { "path": "./stubs/app" },
-    { "path": "./test" },
     { "path": "./ext/app" }
   ],
 }