ESLint rules: array-callback-return, no-invalid-this, func-style (#3151)

* satisfied array-callback-return rule
* satisfying no-invalid-this rule
* fixed invalid-this issues
* changed isNotEqual to arrow function
* added rule func-style
* added return false to satisfy array-callback-return rule

Co-authored-by: Joel McKinnon <jmckinnon@apple.com>
Co-authored-by: Joshi <simplyrender@gmail.com>
Co-authored-by: Andrew Henry <akhenry@gmail.com>

.eslintrc.js

@@ -120,6 +120,12 @@ module.exports = {
         "no-useless-computed-key": "error",
         // https://eslint.org/docs/rules/rest-spread-spacing
         "rest-spread-spacing": ["error"],
+        // https://eslint.org/docs/rules/array-callback-return
+        "array-callback-return": "error",
+        // https://eslint.org/docs/rules/no-invalid-this
+        "no-invalid-this": "error", // Believe this one actually surfaces some bugs
+        // https://eslint.org/docs/rules/func-style
+        "func-style": ["error", "declaration"],
         // https://eslint.org/docs/rules/no-unused-expressions
         "no-unused-expressions": "error",
         // https://eslint.org/docs/rules/no-useless-concat