[BUG][typescript-axios] Generator creates empty interface from anyOf instead of union type

Description

When using the typescript-axios generator, if an OpenAPI schema property has an anyOf with a title attribute, the generator creates a separate empty interface based on that title instead of generating a proper union type.

OpenAPI Specification

{
    "openapi": "3.1.0",
    "info": {
        "title": "Demo",
        "version": "0.1.0"
    },
    "paths": {
        "/users": {
            "get": {
                "summary": "Read Root",
                "operationId": "read_root_users_get",
                "parameters": [
                    {
                        "name": "expand",
                        "in": "query",
                        "required": false,
                        "schema": {
                            "type": "boolean",
                            "default": false,
                            "title": "Expand"
                        }
                    }
                ],
                "responses": {
                    "200": {
                        "description": "Successful Response",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "array",
                                    "items": {
                                        "$ref": "#/components/schemas/UserResponse"
                                    },
                                    "title": "Response Read Root Users Get"
                                }
                            }
                        }
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "Trip": {
                "properties": {
                    "id": {
                        "type": "string",
                        "title": "Id"
                    },
                    "destination": {
                        "type": "string",
                        "title": "Destination"
                    },
                    "date": {
                        "type": "string",
                        "title": "Date"
                    }
                },
                "type": "object",
                "required": [
                    "id",
                    "destination",
                    "date"
                ],
                "title": "Trip"
            },
            "UserResponse": {
                "properties": {
                    "id": {
                        "type": "string",
                        "title": "Id"
                    },
                    "booked_trips": {
                        "anyOf": [
                            {
                                "items": {
                                    "type": "string"
                                },
                                "type": "array"
                            },
                            {
                                "items": {
                                    "$ref": "#/components/schemas/Trip"
                                },
                                "type": "array"
                            }
                        ],
                        "title": "Booked Trips"
                    }
                },
                "type": "object",
                "required": [
                    "id",
                    "booked_trips"
                ],
                "title": "UserResponse"
            }
        }
    }
}

Generator Command

docker run --rm \
  -v "${PWD}:/local" \
  openapitools/openapi-generator-cli generate \
  -i /local/openapi.json \
  -g typescript-axios \
  -o /local/output

Actual Output

export interface Trip {
    'id': string;
    'destination': string;
    'date': string;
}

export interface UserResponse {
    'id': string;
    'booked_trips': UserResponseBookedTrips;
}

export interface UserResponseBookedTrips {
}

Expected Output

The generator should generate a proper union type:

user-response.ts:

import type { Trip } from './trip';

export interface UserResponse {
    'id': string;
    'booked_trips': Array<string> | Array<Trip>;
}

Environment

• OpenAPI Generator version: 7.18.0-SNAPSHOT
• Generator: typescript-axios
• OpenAPI version: 3.1.0

Reproduce the issue with the provided openapi.json and the typescript-axios generator command, then inspect the generated user-response.ts output. Compare the generated booked_trips type with the expected Array | Array union and verify that the empty UserResponseBookedTrips interface is no longer produced.