Build failure against PySide >= 6.8

[misaka18931]

Environment information

• Operating System: NixOS
• Cutter version:
• Obtained from:
  • Built from source
  • Downloaded release from Cutter website or GitHub
  • Distribution repository
• File format:

Describe the bug

PySide::SignalManager::instance() was removed here in this commit, before the release of 6.8.0.

This change in pyside caused a compilation error on cutter/src/common/PythonManager.cpp:136:28 which called PySide::SignalManager::instance().clear();:

/build/source/src/common/PythonManager.cpp:136:28: error: 'instance' is not a member of 'PySide::SignalManager'
  136 |     PySide::SignalManager::instance().clear();

Inferring from code in that same commit, it seems that this line is no longer needed.
But I'm not sure as I'm not familiar with Qt.

To Reproduce

Build cutter against Qt & PySide >= 6.8

Expected behavior

No build failure.

Additional context

The full compilation log can be viewed on the build server of NixOS. link