[PYG-373] 🐛 Generating SDK raise if edge with properties has source not in model (#514)

# Description

**Reviewer**: All code inside `examples/` is generated.

Discovered on the SceneConfiguration model 

## Bump

- [x] Patch
- [ ] Minor
- [ ] Skip

## Changelog
### Fixed

- Generating an SDK for a data model that has a edge with properties
that points to a view that is not in the model no longer raise a
`KeyError`. Instead the user gets a warning and the edge is skipped.
