How to reproduce:
1. Open the project "1065921GCTest.zip" with Unity 2018.1 or earlier
2. Close project and open with Unity 2018.2 or later
3. In the Project go to Packages folder, try to select Analytics library/com.unity.ads/in App Purchasing
Result: It is not possible to select one of it

There are some related issues:
4. Right click TextMesh pro package
5. Select "Reveal in Finder"
6. Delete Analytics 3.0.5 package and go back to Editor
Result:
Once I got the crash, crash log is in Editor.log (but crash doesn't reproduce)
If it doesn't crash, you will get this error
error CS0006: Metadata file `/Users/ieva/Downloads/case_941276-GCTest3/Library/PackageCache/com.unity.analytics@3.0.5/Unity.Analytics.Tracker.dll' could not be found

I tried upgrading this way:
2017.4.7f1 -> 2018.3.0a7 (Reproducible)
2018.1.9f1 -> 2018.2.2f1 (Reproducible)/ 2018.3.0a5 (editor is completely red)/2018.3.0a6 (editor is completely red)/ 2018.3.0a7 (Reproducible)

Tested only on MacBook Pro macOS 10.13.6

WON'T FIX: Issue is provoked by deleting an active folder / dll from a project in motion. When rebooting the project, Analytics will be re-installed