OpenAPI schema generation fails if the GeometryField is not in the model

[AntoninRousset]

This piece of code will cause the schema generation to fail if the GeometryField is not in the model, e.g. it is an annotation or a custom property.

I don't see any simple solution (without custom get_field), beside having multiple serializer fields: PointField, LineStringField, etc.)

[auvipy]

@dhaval-mehta what do you think on this?