`make_dataclass` erase the `__post_init__` method

[vincentsarago]

in #714 we changed how we create GET request model from using attrs to dataclass. This was to support alias with -. The downside was that we need to do validation/conversion in a __post_init__ method.

It seems that this wasn't well tested 😢, and now when we create a Model with extensions the __post_init__ is not ran 😭 😭 😭 😭 😭

from stac_fastapi.api.models import create_get_request_model
from stac_fastapi.extensions.core import FieldsExtension

model = create_get_request_model(extensions=[FieldsExtension()])
model(datetime="yo")


model = create_get_request_model(extensions=[])
model(datetime="yo")

>> HTTPException: 400: Invalid RFC3339 datetime.

where

stac-fastapi/stac_fastapi/api/stac_fastapi/api/models.py

Lines 28 to 50 in 494e485

	def create_request_model(
	model_name="SearchGetRequest",
	base_model: Union[Type[BaseModel], APIRequest] = BaseSearchGetRequest,
	extensions: Optional[List[ApiExtension]] = None,
	mixins: Optional[Union[List[BaseModel], List[APIRequest]]] = None,
	request_type: Optional[str] = "GET",
	) -> Union[Type[BaseModel], APIRequest]:
	"""Create a pydantic model for validating request bodies."""
	fields = {}
	extension_models = []
	# Check extensions for additional parameters to search
	for extension in extensions or []:
	if extension_model := extension.get_request_model(request_type):
	extension_models.append(extension_model)
	mixins = mixins or []
	models = extension_models + mixins + [base_model]
	# Handle GET requests
	if all([issubclass(m, APIRequest) for m in models]):
	return make_dataclass(model_name, [], bases=tuple(models))