How to reproduce:
1. Open the user's attached “AssetPostProcessor Test.zip” project
2. Go to Preferences... > External Tools > External Script Editor and set it to Visual Studio Code
3. In the Preferences window click “Regenerate project files”

Expected result: OnGeneratedSlnSolution and OnGeneratedCSProject methods are called, and debug messages appear in the Console
Actual result: OnGeneratedSlnSolution and OnGeneratedCSProject methods are not called, and no debug messages appear in the Console

Reproducible with: 1.0.7 (2019.31f1, 2020.3.21f1), 1.2.4 (2019.31f1, 2020.3.21f1, 2021.1.26f1, 2021.2.0b16, 2022.1.0a12)
Not reproducible with: 1.0.3 (2020.3.21f1)
Could not test with: 1.0.3 (2019.31f1) (Errors in Console)

Notes:
- To see the expected result repeat steps 2 and 3 just change External Script Editor to Visual Studio at step 2.