Compilation error after generating kotlin code

## Expected Behavior
I would have expected the code generated to compile, but there is a type mismatch

## Current Behavior
The code generated has compile errors

## Possible Solution
Not sure exactly how the codegen works, but it should generate a non-nullable type for the event parameter in the method signature for the identify function, for example:
`open fun identify(userId: String?, event: Identify, options: EventOptions? = null, extra: MiddlewareExtra? = null) `

## Steps to Reproduce
1. create a jvm source
2. add an event
3. add a user property
4. set up the cli tool
5. set up a kotlin project with all required dependencies
6. do ampli pull
7. check the Ampli.kt file, there are compilation errors

## Environment
- Unity Plugin Version: not sure what this is, but i am using com.amplitude:java-sdk:1.10.1
- Device: MACBOOK AIR M1
- Device OS and Version: MONTEREY 12.3