Add `RNSentrySDK` APIs support to `@sentry/react-native/expo` plugin

### Description

The goal of this task is to add support for the new manual APIs in Sentry Expo Plugin.

- Initially as opt-in. `useNativeInit: true`
- The plugin should warn users if native init is already present in the native code.
- The plugin should patch `AppDelegate.mm` for iOS and `MainApplication.kt` for Android.