Add kludge to make testing-library work properly from test-utils package

Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>

packages/core/src/jest-after-env.setup.ts

@@ -4,3 +4,8 @@
  */
 
 import "@testing-library/jest-dom";
+
+// Note: This is a kludge to prevent "Hooks cannot be defined inside tests" error
+// when importing a test util inside a test suite.
+import { render } from "@testing-library/react";
+void render;