Support different OAuth tokens for outgoing/incoming servers (e.g. Outlook with Microsoft Authenticator not working)

Checklist

• I have used the search function to see if someone else has already submitted the same bug report.
• I will describe the problem with as much detail as possible.

App

K-9 Mail

App version

6.804

Where did you get the app from?

Google Play

Android version

LineageOS, Android 12

Device model

No response

Steps to reproduce

1. Have an Outlook account with Microsoft Authenticator enabled
2. Open K-9, go to settings, and tap "Add account"
3. Go through account setup steps

Expected behavior

K-9 should be prompted twice for a password and Authenticator code: once for the incoming server settings, and once for the outgoing server settings. After entering the password twice, and passing the second Authenticator challenge, the server settings should be imported, and the account available in the app.

Actual behavior

K-9 is only prompted for the first password and Authenticator challenge. This causes it to not receive the outgoing server settings, which causes account enrollment in K-9 to fail.

Logs

Start with the account setup flow described in the reproduction steps and trace how incoming and outgoing server authentication are handled during Outlook enrollment. Reproduce the Microsoft Authenticator scenario, then verify that both server prompts and challenges are completed and the account is successfully imported.