[v2 UI] Cannot access pipeline settings page before creating the first event

[yk634]

What happened:
In the v2 UI, attempting to access the pipeline settings page before any event has been created (e.g., immediately after pipeline creation) results in a blank white screen. The URL does not change, and the settings page never loads.

What you expected to happen:
The settings page should open normally, even if no events have been created for the pipeline yet.

How to reproduce it:

1. Create a new pipeline.
2. Attempt to open the pipeline’s settings page.
3. Observe that the page stays blank and the URL does not update.

[yk634]

I checked the browser console (Chrome DevTools) and found that a request to GET /v4/pipelines/<id>/admins returns a 500 error.
Response:

{
    "statusCode": 500,
    "error": "Internal Server Error",
    "message": "WHERE parameter \"id\" has invalid \"undefined\" value"
}

It seems that pipelines with a NULL value for adminUserIds might be causing this error.
Possibly related code:
https://github.com/screwdriver-cd/models/blob/430762e2709b5ce23d6a26e28985e6aa5fe21e04/lib/pipeline.js#L1496