Add missing Headers methods (#43279)

Summary:
```tsx
// Hermes runtime (RN 73.x)
console.log({...Headers.prototype})
// result:
{
  "append": [Function anonymous],
  "delete": [Function anonymous],
  "entries": [Function anonymous],
  "forEach": [Function anonymous],
  "get": [Function anonymous],
  "has": [Function anonymous],
  "keys": [Function anonymous],
  "set": [Function anonymous],
  "values": [Function anonymous],
  Symbol(Symbol.iterator): [Function anonymous]
}
```

But in typescript

```tsx
new Headers().entries()
// ^^^ Error: Property entries does not exist on type Headers
Object.fromEntries(new Headers())
// ^^^ Error: Property [Symbol.iterator] is missing in type Headers but required in type Iterable<readonly any[]>
```

## Changelog:

[GENERAL] [ADDED] - [TypeScript] Add missing `Header` methods

Pull Request resolved: #43279

Test Plan: Use code above in your RN project and run `yarn tsc --noEmit`

Reviewed By: rshest

Differential Revision: D54554523

Pulled By: arushikesarwani94

fbshipit-source-id: ae7f05f9526771ff003aaf22f786b5503661c739

Author: retyui

packages/react-native/types/modules/globals.d.ts

@@ -132,6 +132,10 @@ declare interface Headers {
   get(name: string): string | null;
   has(name: string): boolean;
   set(name: string, value: string): void;
+  entries(): IterableIterator<[string, string]>;
+  keys(): IterableIterator<string>;
+  values(): IterableIterator<string>;
+  [Symbol.iterator](): IterableIterator<[string, string]>;
 }
 
 declare var Headers: {