Integration tests crash on physical iOS devices when using XCode 15

[ivard]

It only occurs on physical iOS devices. No clear exception is being shown. It looks like a silent timeout or something. It happens when the enrollment introduction integration test is starting. That's after the issuance issue-municipality-en test finishes. It's likely that the issue lies in one of these two tests.

The issue occurs both in Firebase Test Lab and in my local setup using my own iPhone, so it is not related to a specific environment.

When compiling with XCode 14.3.1 there are no issues. Upgrading flutter, golang or gomobile to the latest versions does not make a difference.

As a work-around we pinned the XCode version to 14.3.1 in #272 .