chore: remove unused file (#45073)

client/src/__mocks__/gatsby-link.ts

@@ -1,13 +0,0 @@
-/* eslint-disable */
-import React from 'react';
-
-const mockComponent =
-  (name: string) =>
-  (
-    props: React.InputHTMLAttributes<HTMLInputElement> &
-      React.ClassAttributes<HTMLInputElement>
-  ) =>
-    React.createElement(name, props, props.children);
-
-export const navigateTo = () => {};
-export default mockComponent('MockedLink');