Fix build failure against PySide >= 6.8

[karliss]

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• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've updated the documentation with the relevant information (if needed)

Detailed description

Seems like some of the implementation details changed, removing the need for manual cleanup thus the function doesn't exist anymore. pyside/pyside-setup@33bd61d

Test plan (required)

• Still compiles against Pyside < 6.8 - should be covered by CI tests, and the effective code should be identical to before
• Compiles with Pyside 6.8 (need to use CUTTER_ENABLE_PYHON and CUTTER_ENABLE_PYTHON_BINDINGS) - tested on ArchLinux ✔️
• With Pyside 6.8 Cutter exits cleanly without any crashes or new warning messages ✔️

Closing issues

closes #3384

[wargio]

is this clang-formatted ?

[karliss]

Yes, that's why the force push from 441a520 to 198541c. Initially had it without indentation, but Clang formatter in CI complained.

[karliss]

I have to say looks a bit weird especially without additional context.

Seems like in current config clang-format does 4 space indentation (in addition to #) for nested #if blocks. Not a problem for code that contains only preprocessor statements, not a problem if there is single level of #if combined with regular code. But second level of #if mixed with regular code results in the weird off by one indentation you see above.