feat: Introduce FunctionCallback.Builder

[tzolov]

• Introduce FunctionCallback.Builder interface for improved builder pattern.
• Add support for generic type parameters via Type and ParameterizedTypeReference. Enhance function callbacks with generic type support.
• Move CustomizedTypeReference to ModelOptionsUtils for broader reuse.
• Deprecate old FunctionCallbackWrapper.Builder in favor of DefaultFunctionCallbackBuilder.
• Add JSON schema generation support for ResolvableType.
• Update all existing code and tests to use the new FunctionCallback.Builder instead of FunctionCallbackWrapper.Builder
• Removes CustomizedTypeReference which is wrapper that provide little added value, and uses ParameterizedTypeReference instead of ResolvableType in FunctionCallback.Builder#inputType in order to provide a public API that retains generic types.
• Update docs. Replace FunctionCallbackWrapper by Builder
• Adapt inputType() Kotlin extension

Resolves #1731

[markpollack]

fixed kotlin extension that didn't survive the refactoring. Ran tests that changed in the commit.

merged in fb0d99dc3700117ad7100374e84d8f4e4bcbf3ed