Optional field is still `required` in generated model

[zhuscat]

Steps to reproduce

Here is my test swagger file:

{
    "info": {
        "title": "An API",
        "version": "v1"
    },
    "openapi": "3.1.0",
    "components": {
        "schemas": {
            "Foo": {
                "type": "object",
                "properties": {
                    "id": {
                        "type": "string"
                    },
                    "name": {
                        "type": "string"
                    }
                },
                "required": [
                    "id"
                ]
            }
        },
        "parameters": {}
    },
    "paths": {
        "/hello": {
            "get": {
                "responses": {
                    "200": {
                        "description": "Respond a message",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object",
                                    "properties": {
                                        "message": {
                                            "type": "string"
                                        },
                                        "activity": {
                                            "$ref": "#/components/schemas/Foo"
                                        }
                                    },
                                    "required": [
                                        "message",
                                        "activity"
                                    ]
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

The name property of Foo is not required.

Paste the file in Web Interface, and download the zip generated.

Expected results

name is not required

Actual results

name is required

Your OpenApi snippet

{
    "info": {
        "title": "An API",
        "version": "v1"
    },
    "openapi": "3.1.0",
    "components": {
        "schemas": {
            "Foo": {
                "type": "object",
                "properties": {
                    "id": {
                        "type": "string"
                    },
                    "name": {
                        "type": "string"
                    }
                },
                "required": [
                    "id"
                ]
            }
        },
        "parameters": {}
    },
    "paths": {
        "/hello": {
            "get": {
                "responses": {
                    "200": {
                        "description": "Respond a message",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object",
                                    "properties": {
                                        "message": {
                                            "type": "string"
                                        },
                                        "activity": {
                                            "$ref": "#/components/schemas/Foo"
                                        }
                                    },
                                    "required": [
                                        "message",
                                        "activity"
                                    ]
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

Code sample

No response

Logs

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Dart version and used packages versions

I use Web Interface