Automatically restore all Jest mocks after each test

see https://jestjs.io/docs/en/configuration.html#restoremocks-boolean

jest.config.js

@@ -25,4 +25,5 @@ module.exports = {
   modulePathIgnorePatterns: ['<rootDir>/.yarn-cache/'],
   reporters,
   setupTestFrameworkScriptFile: '<rootDir>/spec/frontend/test_setup.js',
+  restoreMocks: true,
 };