[TNL-7268] Remove icon mock

As we're not using snapshots, we will not need this anymore.

src/courseware/course/sequence/sequence-navigation/UnitIcon.test.jsx

@@ -1,5 +1,5 @@
 import React from 'react';
-import { render, screen } from '../../../../setupTest';
+import { render } from '../../../../setupTest';
 import UnitIcon from './UnitIcon';
 
 describe('Unit Icon', () => {
@@ -19,8 +19,8 @@ describe('Unit Icon', () => {
         jest.spyOn(console, 'error').mockImplementation(() => {});
       }
 
-      render(<UnitIcon type={key} />);
-      expect(screen.getByTestId('icon')).toHaveClass(value);
+      const { container } = render(<UnitIcon type={key} />);
+      expect(container.querySelector('svg')).toHaveClass(value);
     });
   });
 });

src/test/__mocks__/@fortawesome/react-fontawesome.js

@@ -1,32 +0,0 @@
-/**
- * Mocks `@fortawesome/react-fontawesome.js` to return a simple <img> element containing `data-testid` attribute.
- * This way we can check whether the icon matches without relying on its internal implementation
- * and avoid storing its <svg> content in the snapshot tests.
- */
-import React from 'react';
-import PropTypes from 'prop-types';
-
-// eslint-disable-next-line no-use-before-define
-FontAwesomeIcon.propTypes = {
-  icon: PropTypes.oneOfType([
-    PropTypes.string,
-    PropTypes.shape({
-      icon: PropTypes.arrayOf(PropTypes.any),
-    }),
-  ]).isRequired,
-};
-
-// eslint-disable-next-line import/prefer-default-export
-export function FontAwesomeIcon(props) {
-  const { icon } = props;
-
-  let iconName;
-  if (typeof icon === 'string') {
-    iconName = icon;
-  } else {
-    iconName = `fa-${icon.iconName}`;
-  }
-
-  // eslint-disable-next-line react/jsx-filename-extension
-  return <svg data-testid="icon" className={iconName} />;
-}