[Feature]: Allow values in @ExampleObject to be read from a file

Feature Description

I would like to see a way to define example payloads in the @ExampleObject annotation from a file, rather than declaring constants for it.

• What problem does it solve?
  For APIs with larger payloads, defining payloads with @ExampleObjects becomes unmanageable because the examples must be defined as constants, resulting in boilerplate code in Java classes.
• How would it improve swagger-core?
  It will make it easier to maintain large example payloads without creating constants in Java.
• Is it related to OpenAPI spec support, annotation improvements, integration, etc.?
  It would be categorized as annotation improvement.

Use Case

@ExampleObject ( description = "test description", file = "classpath:/main/resources/openapi/test-example.json")

Suggested Solution (optional)

Add a feature in the @ExampleObject annotation to read a value from a file.

Alternatives Considered

Additional Context

Checklist

• I have searched the existing issues to ensure this is not a duplicate.
• This feature would be useful to more than just my use case.
• I have provided enough detail for the maintainers to understand the scope of the request.

Start by locating the @ExampleObject annotation and the code that processes its example values. Check the related annotation tests, then verify that a file or classpath resource can supply the example payload while preserving the existing description behavior.