fix: Ensure non-null collection schema type

## What kind of change does this PR introduce? Bug fix ## What is the current behavior? Exposed GraphQL schema exposes a nullable type for pagable collection wrapper objects ## What is the new behavior? The schema type is now a non-null type ## Additional context note the `!` annotations in the collection return types | Before | After | | --- | --- | | <img width="388" height="882" alt="image" src="https://github.com/user-attachments/assets/35a09d22-4bb0-4f24-b1fd-f59fcf93ba58" /> | <img width="388" height="882" alt="image" src="https://github.com/user-attachments/assets/ca6af2cd-bbeb-4237-aa2e-aa93dc91505e" /> |