Publicize: Flow to connect a Facebook account never completes

[renanferrari]

Expected behavior

Logging in with a Facebook account through the Publicize web flow should return to the app after the login, and the Facebook account should be available be made available to the user.

Actual behavior

The web flow to connect a new Facebook account never returns to the app after successfully logging in with Facebook:

IMG_0102.MP4

Steps to reproduce the behavior

1. Open the app and select a WP.com or Jetpack site.
2. On the My Site screen, scroll down to the Configuration section.
3. Tap "Sharing".
4. Tap "Facebook".
5. Tap "Connect".
6. Login with a Facebook account that has at least one page.
7. Accept all Facebook permissions.
8. Notice how the web flow gets stuck and never returns to the app.

Additional context

This was caused by a change to the parameters of the URL used to create a new Facebook connection (internal ref: r238579-wpcom). Assuming the implementation on iOS is similar to what we have on Android, then the end of the web flow is detected based on some URL pattern. The fix should be to update this logic to take the new URL structure into account.

Tested on iPad Pro 11in, iOS 15.1, WPiOS 19.0