Improve order of drop-down items when using discriminator (since #1462 is closed)

Describe the bug
Please refer to https://github.com/Redocly/redoc/issues/1462 for the description.

Expected behavior
The dropdown is shown in the reverse order in some cases.

Minimal reproducible OpenAPI snippet(if possible)

I created a test schema that can be used to reproduce the problem.

Attached please find the redoc-issue-1462.yaml.txt file that contains one API endpoint which is a simplified version of the "new pet" for the pet store example.

Can you download the file, remove the .txt extension, and test it? Github doesn't allow uploading YAML file.

A few differences between this sample schema and the openapi.yaml for the pet store:

• First, requestBodies is not used for the request body schema, e.g., "#/components/requestBodies/Pet". I set it to "#/components/schemas/requestBody" instead
• The requestBody schema contains oneOf and discriminator with mapping,
• The petType field is defined in the Cat, Dog, and Honeybee schemas with the enum values set.

Screenshots

Below are the screenshots showing the problem. I used the "OpenAPI ​(Swagger)​ Editor" IntelliJ plugin to show the problem on the Chrome browser.

1. Problem: The dropdown shows "bee", "dog", and "cat" from the sample schema, though "cat" is the default.
   The expected list is "cat", "dog", and "bee".

Compared to the [redoc-issue-1462.yaml.txt](https://github.com/Redocly/redoc/files/14381183/redoc-issue-1462.yaml.txt) (pet store) which shows the dropdown properly.

2. No problem with the example dropdown on the right pane. (Good)

Additional context
Add any other context about the problem here.

redoc-issue-1462.yaml.txt

Start by loading redoc-issue-1462.yaml.txt, after removing its .txt extension, in Redoc and compare the discriminator dropdown with the expected order. Trace the dropdown entry point for the requestBody schema using oneOf and discriminator mapping; done means the list displays cat, dog, then bee while the existing example dropdown remains unchanged.