Bug 488226

SUMMARY

Found something strange introduced by commit [426f99638a1fa712a6d8ded0eb9a523ef160551b](https://invent.kde.org/graphics/krita/-/commit/426f99638a1fa712a6d8ded0eb9a523ef160551b).

Execute the following script:
```python
from krita import Document

import os.path

newDoc = Krita.instance().createDocument(500, 500, "Test", "RGBA", "U8", "", 300)
newDoc.saveAs(os.path.expanduser("~/test.kra"))
newDoc.close()
```
On Krita built after this commit,  it generate the following warnings (message print 3 times):
```text
WARNING: the destination object of KisSynchronizedConnection has been destroyed during postponed delivery
WARNING: the destination object of KisSynchronizedConnection has been destroyed during postponed delivery
WARNING: the destination object of KisSynchronizedConnection has been destroyed during postponed delivery
```

Before this commit, there's no warnings.

I've tried to understand, but I'm not able to understand the relation ship with Python API here (close an opened document from UI doesn't generate warnings)

STEPS TO REPRODUCE
1. Activate log docker to get warning messages
2. Execute script in scripter


OBSERVED RESULT

Warnings message are produced

EXPECTED RESULT

No warning message

ADDITIONAL INFORMATION
Found commit with git bisect + build appimage