[BUG][Python] anyOf for string/array of strings not rendered correctly

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

I have a schema KeyValuePair which specifies that a property can either be a string or a list of strings:

  anyOf:
            - items:
                type: string
              type: array
            - type: string

When rendering the Python client, this is turned into:

    value: Optional[StrictStr]

Instead, I would expect this to be rendered to:

    value: str | List[str]

openapi-generator version

7.3.0-SNAPSHOT

OpenAPI declaration file content or url

openapi: 3.1.0
info:
  title: Test
  version: 1.0.0
paths:
  /:
    get:
      tags:
        - collections
      responses:
        '200':
          description: Request successful
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/KeyValuePair'
components:
  schemas:
    KeyValuePair:
      properties:
        key:
          type: string
          title: Key
        value:
          anyOf:
            - items:
                type: string
              type: array
            - type: string
          title: Value
      type: object
      required:
        - key
        - value
      title: KeyValuePair

Generation Details

docker run --rm \
    -v $(pwd):/local openapitools/openapi-generator-cli:latest generate \
    -i ./local/swagger.yaml \
    -g python \
    -o /local/out/test \
    --additional-properties generateSourceCodeOnly=true

Steps to reproduce

• Put swagger pasted above int ofile
• Run docker command above
• Inspect file: cat out/test/openapi_client/models/key_value_pair.py

Related issues/PRs

Suggest a fix

Start with the provided OpenAPI declaration and reproduce the issue using the Docker generation command for the Python client. Inspect out/test/openapi_client/models/key_value_pair.py and trace how the value property's anyOf schema is rendered. Done means the generated model represents both a string and a list of strings instead of only StrictStr.