refactor: migrate ModuleNode to use strawberry-django decorator for consistency

## Problem
`ModuleNode` in `backend/apps/mentorship/api/internal/nodes/module.py` is currently
implemented using the base `@strawberry.type` decorator with manually defined fields
and a TODO comment left by @arkid15r:
```python
# TODO (@arkid15r ): migrate to decorator for consistency.
id: strawberry.ID
```

## Proposed Solution
Migrate `ModuleNode` to use `@strawberry_django.type(Module, ...)` instead of
`@strawberry.type`, aligning it with the pattern used in other nodes in the codebase.

## Additional Context
A similar refactor for `MenteeNode` is tracked in #3555. This issue covers the
equivalent change for `ModuleNode`.

## Are you going to work on implementing this?
- [x] Yes