Allow users to close the settings dialog without filling all settings

[leendertvanwolfswinkel]

2212 0139

User says:

When logging in via the 3Di Models & Simulations plugin, I was asked to set a Personal API Key. However, I didn't have this one yet and that's why I clicked Cancel. That will just tell me again that I need to fill in all settings.

The screen also did not want to close, not even by clicking on the x button at the top-right of the screen. Adding a working directory did not solve the problem either. In the end I even had to close QGIS with the task manager.