readOnly property not marked as optional in the generated model

Describe the bug
Fields marked as readOnly in a schema in the OpenAPI document are not set as optional in the generated model.
This makes them required in the body of any POST request in which this model is used, defeating the purpose of using the readOnly property.

OpenAPI Spec File

openapi: 3.1.0
info:
  title: Minimal bug reproduction API
  version: 1.0.0
paths:
  /bug:
    get:
      summary: Get all bugs
      responses:
        "200":
          description: A list of bugs
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/Bug"
    post:
      summary: Create a bug
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/Bug"
      responses:
        "201":
          description: Bug created
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Bug"

components:
  schemas:
    Bug:
      type: object
      properties:
        id:
          readOnly: true
          type: integer
        created_at:
          readOnly: true
          type: string
          format: date-time
        name:
          type: string
        description:
          type: string
        status:
          type: string
          enum:
            - open
            - closed
      required:
        - id
        - name
        - description
        - status
        - created_at

Desktop (please complete the following information):

• OS: [Windows 11]
• Python Version: [3.12]
• openapi-python-client version [0.22]

Begin by running the supplied OpenAPI 3.1 reproduction with openapi-python-client 0.22 and inspecting the generated Bug model and POST usage. Trace where readOnly and required fields are converted; done when readOnly fields are not required for POST input while remaining available in generated response models, with regression coverage.