fix(iOS): remove unused RCTTurboModuleManagerDelegate method (#48290)

Summary:
Hey, this PR removes unused method from RCTAppDelegate.

The only called method from RCTTurboModuleManagerDelegate is `getTurboModule:jsInvoker`, the `getTurboModule:initParams:` is never called.

https://github.com/facebook/react-native/blob/5a81ceed2a6c974211e6a238efee3eea68b9568a/packages/react-native/ReactCommon/react/runtime/platform/ios/ReactCommon/RCTInstance.mm#L207

## Changelog:

[INTERNAL] [REMOVED] - remove unused RCTTurboModuleManagerDelegate method

Pull Request resolved: https://github.com/facebook/react-native/pull/48290

Test Plan: CI Green, ensure everything works as before

Reviewed By: javache

Differential Revision: D67392056

Pulled By: cipolleschi

fbshipit-source-id: e7f35f81c48cdc163cfff45987e0b7eb022cbf7d