extracted nullguard function to parsers-util.js file (#34952)

Summary:
This PR is a part of #34872
This PR extracts Extract the `nullGuard` function ([Flow](https://github.com/facebook/react-native/blob/main/packages/react-native-codegen/src/parsers/typescript/modules/index.js#L74-L76), [TypeScript](https://github.com/facebook/react-native/blob/main/packages/react-native-codegen/src/parsers/typescript/modules/index.js#L74-L76)) into a function in the `parsers-utils.js` file

## Changelog
[Internal] [Changed] - Extracted `nullGuard` function from flow and typescript to a file `parsers-utils.js`.

Pull Request resolved: #34952

Test Plan:
yarn jest react-native-codegen
<img width="1042" alt="Screenshot 2022-10-12 at 12 52 02 PM" src="https://user-images.githubusercontent.com/22423684/195277414-dc0122f4-603a-4e93-aef1-2ac0c33a960d.png">

Reviewed By: NickGerleman

Differential Revision: D40296951

Pulled By: cipolleschi

fbshipit-source-id: 4fb305fff2e28025496b65ec697d2a59cff77bde

Author: dakshbhardwaj

packages/react-native-codegen/src/parsers/flow/modules/index.js

@@ -24,6 +24,7 @@ import type {
 
 import type {ParserErrorCapturer, TypeDeclarationMap} from '../../utils';
 import type {NativeModuleTypeAnnotation} from '../../../CodegenSchema.js';
+const {nullGuard} = require('../../parsers-utils');
 
 const {throwIfMoreThanOneModuleRegistryCalls} = require('../../error-utils');
 const {
@@ -76,10 +77,6 @@ const {
 
 const language = 'Flow';
 
-function nullGuard<T>(fn: () => T): ?T {
-  return fn();
-}
-
 function translateArrayTypeAnnotation(
   hasteModuleName: string,
   types: TypeDeclarationMap,

packages/react-native-codegen/src/parsers/parsers-utils.js

@@ -0,0 +1,19 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow strict
+ */
+
+'use strict';
+
+function nullGuard<T>(fn: () => T): ?T {
+  return fn();
+}
+
+module.exports = {
+  nullGuard,
+};

packages/react-native-codegen/src/parsers/typescript/modules/index.js

@@ -24,6 +24,7 @@ import type {
 
 import type {ParserErrorCapturer, TypeDeclarationMap} from '../../utils';
 import type {NativeModuleTypeAnnotation} from '../../../CodegenSchema.js';
+const {nullGuard} = require('../../parsers-utils');
 
 const {throwIfMoreThanOneModuleRegistryCalls} = require('../../error-utils');
 const {
@@ -76,10 +77,6 @@ const {
 
 const language = 'TypeScript';
 
-function nullGuard<T>(fn: () => T): ?T {
-  return fn();
-}
-
 function translateArrayTypeAnnotation(
   hasteModuleName: string,
   types: TypeDeclarationMap,