Job Failed #2524285947: CopyItemQuery test randomly fails

Job #2524285947 failed for 99df1d4c:

The CopyItemQuery test case randomly fails - for now, this seems to happen on Mac OS X only, but other platforms might be affected as well.

👉 We still have some occurrences in the code, where we connect a signal to a lambda expression or other callable but don't specify a context object. This could potentially explain this kind of random failures. We should check if we can integrate e.g. the clazy checker into our CIs to get a quick insight in where we use this kind of anti-pattern (on top, it also would warn of other issues we might have in the code).