Upgraded role is assigned immediately, even if "Nur bei erfolgreicher Zahlung durchführen" is enabled in Up-/Downgrade

Problem/Motivation

We need to check our webhook listeners. It's absolutely possible that the reason is on the Billwerk side, this isn't clear yet.
Or we have to change the event listeners implementation.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes