Blank __/auth/handler

### Operating System

macOS Ventura 13.2.1

### Browser Version

Chrome Version 115.0.5790.114,

### Firebase SDK Version

9.23.0

### Firebase SDK Product:

Auth

### Describe your project's tooling

React app with Vite and Vite PWA Plugin

### Describe the problem

I have the same issue with https://github.com/firebase/firebase-js-sdk/issues/7273. Yet I also tried his approach and did not shed any light. We (the team) are publishing a PWA to iOS via https://www.pwabuilder.com/, everything is going fine with the firebase auth SSO (google and apple) across different browsers such as Chrome and Safari, the firebase auth also works on the installed versions of the PWA, and as well as the published PWA on Google Play Store. However, the user redirects on a blank screen on the __/auth/handler when accessed on a native iOS WebView. We also confirmed that on the native iOS version, it opens an in-app browser. signInwithPopup() flow is used. I can send the url via email, contact me at dexcabigting1234@gmail.com

### Steps and code to reproduce issue

1. Enter pwabuilder.com
2. Enter URL
3. Click package for stores
4. Select iOS then generate package
5. Add permitted URLS in the "All Settings" dropdown [accounts.google.com, appleid.apple.com, sandbox.paypal.com]
6. Download package
7. Open the zip file and open a terminal in the src folder
8. Type pod install on the terminal (make sure you are in the src folder and have cocoapods installed)
9. Open .xcworkspace file on Xcode, run on iOS. 14+
10. Sign in with either google or apple
11. Then the __/auth/handler should be blank