Revert (Jest) test back to original form and patch it up

packages/load/tests/use-custom-loader.spec.ts

@@ -1,12 +1,9 @@
-import { useCustomLoader } from '../src/utils/custom-loader.js';
+import { getCustomLoaderByPath } from '../src/utils/custom-loader.js';
 
-describe('useCustomLoader', () => {
-  it.each(['cjs', 'mjs'])(
-    'can load a custom loader from a file path',
-    async (extension: string) => {
-      const loader = await useCustomLoader(`./custom-loader.${extension}`, __dirname);
-      const result = await loader('some-name', { customLoaderContext: {} });
-      expect(result).toEqual('I like turtles');
-    },
-  );
+describe('getCustomLoaderByPath', () => {
+  it('can load a custom loader from a file path', async () => {
+    const loader = await getCustomLoaderByPath('./custom-loader.cjs', __dirname);
+    expect(loader).toBeDefined();
+    expect(loader('some-name', { customLoaderContext: {} })).toEqual('I like turtles');
+  });
 });