Missing import when there is a const in the object

Describe the bug
Version: 0.21.1
When I try to generate a client it fails with the following error:
Error(s) encountered while generating, client was not created

ruff failed

rivery_scim_client/models/book.py:40:21: F821 Undefined name cast
Found 209 errors (208 fixed, 1 remaining).

As you can see there is an import missing. I publish a PR that should solve it.
https://github.com/openapi-generators/openapi-python-client/pull/1072

OpenAPI Spec File
I created a dummy openapi specification.

{
    "openapi": "3.1.0",
    "info": {
        "title": "FastAPI",
        "version": "0.1.0"
    },
    "paths": {
        "/books": {
            "post": {
                "summary": "Create User",
                "operationId": "create_user_books_post",
                "requestBody": {
                    "content": {
                        "application/json": {
                            "schema": {
                                "$ref": "#/components/schemas/Book"
                            }
                        }
                    },
                    "required": true
                },
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {}
                            }
                        }
                    },
                    "422": {
                        "description": "Validation Error",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "$ref": "#/components/schemas/HTTPValidationError"
                                }
                            }
                        }
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "Book": {
                "properties": {
                    "item_type": {
                        "const": "book",
                        "title": "Item Type",
                        "default": "book"
                    }
                },
                "type": "object",
                "title": "Book"
            },
            "ErrorResponse": {
                "properties": {
                    "schemas": {
                        "items": {
                            "type": "string"
                        },
                        "type": "array",
                        "title": "Schemas",
                        "default": [
                            "urn:ietf:params:scim:api:messages:2.0:Error"
                        ]
                    },
                    "status": {
                        "type": "integer",
                        "title": "Status"
                    },
                    "details": {
                        "type": "string",
                        "title": "Details"
                    }
                },
                "type": "object",
                "required": [
                    "status",
                    "details"
                ],
                "title": "ErrorResponse"
            },
            "HTTPValidationError": {
                "properties": {
                    "detail": {
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        },
                        "type": "array",
                        "title": "Detail"
                    }
                },
                "type": "object",
                "title": "HTTPValidationError"
            },
            "ValidationError": {
                "properties": {
                    "loc": {
                        "items": {
                            "anyOf": [
                                {
                                    "type": "string"
                                },
                                {
                                    "type": "integer"
                                }
                            ]
                        },
                        "type": "array",
                        "title": "Location"
                    },
                    "msg": {
                        "type": "string",
                        "title": "Message"
                    },
                    "type": {
                        "type": "string",
                        "title": "Error Type"
                    }
                },
                "type": "object",
                "required": [
                    "loc",
                    "msg",
                    "type"
                ],
                "title": "ValidationError"
            }
        },
        "securitySchemes": {
            "HTTPBearer": {
                "type": "http",
                "scheme": "bearer"
            }
        }
    }
}

Additional context
Add any other context about the problem here.
N/A

Start with the provided OpenAPI specification and inspect the generated rivery_scim_client/models/book.py, especially the undefined cast reference reported at line 40. Compare the behavior with pull request 1072 and verify generation succeeds without the F821 error and that the generated client passes Ruff.