Remove unused and incorrect type declarations (#32570)

Summary:
See #32566

This file doesn't have a `flow` comment, and the types that I removed here are incorrect anyway (missing a generic type parameter) because Flow didn't check them.

## Changelog

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[General] [Fixed] - Remove unused and incorrect type declarations in WebSocketInterceptor

Pull Request resolved: #32570

Test Plan: See #32566

Reviewed By: lunaleaps

Differential Revision: D32315077

Pulled By: GijsWeterings

fbshipit-source-id: d3b826a01a0bb8e38380de5b79cb6b5d13db2ef1

Libraries/WebSocket/WebSocketInterceptor.js

@@ -17,8 +17,8 @@ const originalRCTWebSocketSend = NativeWebSocketModule.send;
 const originalRCTWebSocketSendBinary = NativeWebSocketModule.sendBinary;
 const originalRCTWebSocketClose = NativeWebSocketModule.close;
 
-let eventEmitter: NativeEventEmitter;
-let subscriptions: Array<EventSubscription>;
+let eventEmitter;
+let subscriptions;
 
 let closeCallback;
 let sendCallback;