Fix TurboModuleRegistry TS type (#35885)

Summary:
TurboModuleRegistry export functions and not a TurboModuleRegistry object. See https://github.com/facebook/react-native/blob/main/Libraries/TurboModule/TurboModuleRegistry.js#L37

## Changelog

[GENERAL] [FIXED] - Fix TurboModuleRegistry TS type

Pull Request resolved: #35885

Test Plan:
Tested that the import doesn't generate a type error when used correctly.

```ts
import * as TurboModuleRegistry from 'react-native/Libraries/TurboModule/TurboModuleRegistry';

export default TurboModuleRegistry.get<Spec>('RNCSafeAreaContext');
```

Reviewed By: christophpurrer

Differential Revision: D42604208

Pulled By: NickGerleman

fbshipit-source-id: e6259df24aaf6e37b32cc4b51947294fd655837e

Libraries/TurboModule/TurboModuleRegistry.d.ts

@@ -9,7 +9,5 @@
 
 import {TurboModule} from './RCTExport';
 
-export const TurboModuleRegistry: {
-  get<T extends TurboModule>(name: string): T | null;
-  getEnforcing<T extends TurboModule>(name: string): T;
-};
+export function get<T extends TurboModule>(name: string): T | null;
+export function getEnforcing<T extends TurboModule>(name: string): T;

types/index.d.ts

@@ -136,7 +136,7 @@ export * from '../Libraries/StyleSheet/StyleSheetTypes';
 export * from '../Libraries/StyleSheet/processColor';
 export * from '../Libraries/Text/Text';
 export * from '../Libraries/TurboModule/RCTExport';
-export * from '../Libraries/TurboModule/TurboModuleRegistry';
+export * as TurboModuleRegistry from '../Libraries/TurboModule/TurboModuleRegistry';
 export * from '../Libraries/Types/CoreEventTypes';
 export * from '../Libraries/Utilities/Appearance';
 export * from '../Libraries/Utilities/BackHandler';