When you have Custom Connection and use SelectField, Connection screen becomes unusable (see #17064) 

We should detect the situation and throw an exception when Provider Info is initialized.
airflow/providers_manager.py
"""Creates JSON schema validator from the provider_info.schema.json"""
    schema = json.loads(importlib_resources.read_text('airflow', 'provider_info.schema.json'))
    cls = jsonschema.validators.validator_for(schema)
    validator = cls(schema)
    return validator
def _create_customized_form_field_behaviours_schema_validator():
    """Creates JSON schema validator from the customized_form_field_behaviours.schema.json"""
    schema = json.loads(
        importlib_resources.read_text('airflow', 'customized_form_field_behaviours.schema.json')
    )
    cls = jsonschema.validators.validator_for(schema)
    validator = cls(schema)
    return validator
class ProviderInfo(NamedTuple):
    """Provider information"""
    version: str
    provider_info: Dict
class HookInfo(NamedTuple):
    """Hook information"""
    connection_class: str
    connection_id_attribute_name: str
    package_name: str
    hook_name: str
class ConnectionFormWidgetInfo(NamedTuple):
    """Connection Form Widget information"""
    connection_class: str
    package_name: str
    field: Field
class ProvidersManager: