[2D] [Sprite Shape] Importing Sprite Shape Extras will throw "Reload Assembly called from managed code directly" error

If the user elects to install the Sprite Shape Extras sample from package manager, an exception will be thrown about calling Reload Assembly from managed code.

Steps to reproduce:
- Open the attached project OR create a new 2D project and install the Sprite Shapes package via the package manager
- In the Package Manager, locate the Sprite Shapes package and in the description, under Samples, and select "Import in project" on the "Sprite Shape Extras
- Observe the following exception printed to console:

Reload Assembly called from managed code directly. This will cause a crash. You should never refresh assets in synchronous mode or enter playmode synchronously from script code.
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)