[BUG] [typescript] Regression: Enums in query parameters are handled as objects

[bodograumann]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

In #19519 (generator v7.9.0; @joscha) the serialization of query parameters was changed. This has broken the serialization of enum fields in query parameters, at least in some situations.
Still investigating the exact cause.

openapi-generator version

Found in v7.12.0, but seems to be caused by the change in v7.9.0.

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

WIP

Related issues/PRs

#19519

Suggest a fix

[bodograumann]

Seems this is already fixed in #20210. Closing.