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

[krystofwoldrich]

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.