the latest dev not working with conda python 3.12

[nnhjy]

As the title indicates, running spinetoolbox fails with "Exit Code 1" with the installations below. The same spine packages work with conda python 3.11.

Python: Python 3.12.3 | packaged by Anaconda, Inc. | (main, May 6 2024, 19:42:21) [MSC v.1916 64 bit (AMD64)] on win32 spine_engine 0.25.0.dev8+g106b313
spine_items 0.22.2
spinedb_api 0.32.0.dev1+gdfbb3b0 spinetoolbox 0.9.0.dev1+g5a5f652ea