Adjust glob used to exclude frontend-shared tests from typechecking

Change the glob to allow for `test/` dirs inside subdirectories of
`frontend-shared/src`.

src/tsconfig.json

@@ -20,6 +20,6 @@
     "**/test/**/*.js",
     "test-util/**/*.js",
     "karma.config.js",
-    "../frontend-shared/src/test/**/*.js",
+    "../frontend-shared/src/**/test/*.js",
   ]
 }