Feature Request: Option to expand only request parameters by default

I would like to propose a new feature for the ReDoc documentation generator. Currently, there is an option to expand all objects in the documentation by default using the expandResponses and requiredPropsFirst settings. However, I think it would be beneficial to have an option to expand only request parameters by default, without expanding other objects.

Use case:
As a user, when I'm browsing API documentation, I often find it most helpful to see the request parameters first, as they provide the essential information for making API calls. Expanding only request parameters would make it easier for users to quickly understand and utilize the API.

Proposed solution:
Introduce a new option or setting (e.g., expandRequestParameters) that, when enabled, would expand all request parameters by default while leaving other objects collapsed. This option could be set in the ReDoc configuration, like this:

html
<redoc spec-url='path/to/your/spec.yml' expand-request-parameters></redoc>
Thank you for considering this feature request. I believe it would be a valuable addition to the ReDoc project and improve the overall user experience.

Start by tracing the existing expandResponses and requiredPropsFirst configuration paths in ReDoc. Confirm the new setting expands request parameters while leaving other objects collapsed, and add coverage for the HTML attribute and configuration behavior described in the issue.