[bug][symfony] AnyType is not defined

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

AnyType is not defined in symfony server generated code.
In some situations, schemas return any, this is handled in other languages where that is translated into something the language understands, examples:

• Java: Object
• C#: `Object
• Rust: serde_json:Value

However, this translation is not made for symfony, and the generators write AnyType in such situations, leading to type errors:
AnyType is not defined anywhere.

openapi-generator version

7.2.0

some_data:
      type: object
      additionalProperties: true

or

some_data:
      type: object
      additionalProperties: {}

when a request is made with some data , this exception is thrown by JMSSerializer in vendor/jms/metadata/src/MetadataFactory.php

curl --location --request POST 'http://localhost:8000/myservice' \
--header 'Content-Type: application/json' \
--data-raw '{
  "some_data": {
    "additionalProp1": "string",
    "additionalProp2": "string",
    "additionalProp3": "string"
  }
}'

Uncaught PHP Exception ReflectionException: "Class "AnyType" does not exist" at MetadataFactory.php line 175

Generation Details

openapi-generator-cli \                        
    generate \
    -i openapi.yaml \
    -g php-symfony \
    -o .

Steps to reproduce

Related issues/PRs

its the same issue as this one was for typescript https://github.com/OpenAPITools/openapi-generator/issues/6332

Start by running the supplied openapi-generator command with the php-symfony generator and the example schema using additionalProperties. Trace the generated type through the request handling that reaches vendor/jms/metadata/src/MetadataFactory.php. Done means generated Symfony code no longer refers to an undefined AnyType and the shown POST payload can be handled successfully.