How to reproduce:
1. Create an empty 3D Project
2. Open the "SampleScene"
3. Open the Package Manager and install the Polybrush package
4. Observe the Console

Expected result: No critical errors appear
Actual result: Critical errors appear in the Console window

Reproducible in: 2021.3.0f1, 2021.3.17f1
Not reproducible in: 2021.2.19f1, 2021.3.18f1, 2021.3.46f1, 2022.3.52f1, 6000.0.28f1, 6000.1.0a5
Fixed in: 2021.3.18f1

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Notes:

* Bug is only reproducible using Polybrush package versions 1.1.6 and 1.1.8
* Bug is not reproducible with earlier package versions