Fix eslint files for prettier (#8815)

* Fixed lint extends so that prettier is the last extends to override all other extends (recommended).

* Added prettier to extends of base eslint file.

.eslintrc.js

@@ -3,7 +3,7 @@ module.exports = {
     browser: true,
     es6: true,
   },
-  extends: 'eslint:recommended',
+  extends: ['eslint:recommended', 'prettier'],
   globals: {
     Atomics: 'readonly',
     SharedArrayBuffer: 'readonly',

app/javascript/.eslintrc.js

@@ -1,6 +1,6 @@
 module.exports = {
   parser: 'babel-eslint',
-  extends: ['airbnb', 'prettier', 'plugin:jsx-a11y/recommended'],
+  extends: ['airbnb', 'plugin:jsx-a11y/recommended', 'prettier'],
   parserOptions: {
     ecmaVersion: 2017,
   },