DirectoryNotFoundException thrown when installed package declares samples that don't exist on disk

Steps to reproduce:

1. Open a project with any UPM package installed that declares samples in its package.json
2. Delete the package's Samples~/ directory from disk
3. Trigger a package refresh

Actual results: 

DirectoryNotFoundException is thrown: Could not find a part of the path '{resolvedPackagePath}/Samples~/{SampleName}'

Expected results: 

No error. Samples that don't exist on disk used to be silently skipped and would only fail when trying to import them.

Reproducible with versions: 

6000.5.0a8+

Not reproducible with versions: 

Versions prior to 6000.5.0a8

Can’t test with versions: 

Tested on (OS): 

macOS ARM64