`signInWithPopup` flow rejects with `auth/popup-closed-by-user` after around 8 seconds

### Operating System

macOS 14.5 (23F79)

### Browser Version

Chrome version 126.0.6478.127 (Official Build) (arm64)

### Firebase SDK Version

10.12.3

### Firebase SDK Product:

Auth

### Describe your project's tooling

A bare Next.js (14.2.5) project

### Describe the problem

In our project we are using a custom OIDC provider for `OpenID Connect` that's called [Somtoday](https://somtoday.nl/)

Their OpenID configuration can be found at: https://somtoday.nl/.well-known/openid-configuration

When initiating the popup sign-in flow the user gets some sort of timeout after around 8 seconds, regardless of what the user is doing (nothing or filling in their credentials within the popup).

A video of the process can be found here: https://youtu.be/qe0TWhU3l-k

### Steps and code to reproduce issue

A minimal reproducible example: https://github.com/aike19115/example-firebase-oidc

1. Call the `signInWithPopup` function
2. Wait for around 8 seconds and the error appears

Start with the minimal reproducible example and the signInWithPopup call, then reproduce the timeout using the Somtoday OpenID configuration described in the issue. Trace the Firebase Auth popup flow to determine why it rejects after about eight seconds, and verify that the same OIDC sign-in remains active while credentials are entered and completes successfully.

Written by the indexing model from the issue text.