Schema is always overridden in the samples when using `allOf` in the preview

Describe the bug

I am extending a component schema by using allOf. The first component definition (TestPage) contains a property with type, properties and the rest of the schema of the component. The second (Page) one only contains the same property with only a description, which I want to be the same for all extending objects. When using the preview command in the cli, the document I see in the browser has a response sample with said overridden property marked as null, regardless of its definition.

To Reproduce
Steps to reproduce the behavior:

1. Given this redocly.yaml file
   None

2. And this OpenAPI file(s)

openapi: 3.1.0
info:
  title: Test
  version: 1.0.0
paths:
  /test:
    get:
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TestPage'
components:
  schemas:
    Page:
      type: object
      properties:
        page:
          type: integer
        total:
          type: integer
        content:
          description: Awesome description
    TestPage:
      allOf:
        - type: object
          properties:
            content:
              type: array
              items:
                $ref: '#/components/schemas/TestSummary'
        - $ref: '#/components/schemas/Page'
    TestSummary:
      type: object
      properties:
        id:
          type: integer
        name:
          type: string

3. Run this command with these arguments... redocly ...

redocly preview-docs openapi.yaml

4. See error
   The generated response sample for status 200 is this:

{
  "content": null,
  "page": 0,
  "total": 0
}

Expected behavior

I expected the property content declared in TestPage to contain its definition, regardless of being overridden in Page, since the second doesn't contain a schema.

{
  "content": [
    {
      "id": 0,
      "name": "This is a test"
    }
  ],
  "page": 0,
  "total": 0
}

Logs
-

OpenAPI description
-

Redocly Version(s)

1.19.0

Node.js Version(s)

v20.13.1

Additional context
-

Reproduce the issue with the supplied OpenAPI document by running redocly preview-docs openapi.yaml and inspect the preview response-sample generation for allOf schemas. Trace how the content property is resolved, then verify that the generated sample preserves the array of TestSummary objects while retaining the description from Page.