Fix 1815 - Get-InstalledPSResource -Path don't throw if no subdirectories were found

[o-l-a-v]

PR Summary

Don't throw if no subdirectories are found.

This code is a bit confusing though, I don't get why it searches for version directories with no validation logic.

https://github.com/o-l-a-v/PowerShell--PSResourceGet/blob/3d28924d4d90b05911dc0f1a40bcff14e927dfc0/src/code/GetInstalledPSResource.cs#L101-L111

I won't try to rewrite that, as I'm sure it has a purpose. I'll just make the error non terminating.

PR Context

Closes #1815

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[alerickson]

The following test is currently failing:

Should not throw on ErrorAction ignore when no subdirectories are found 4ms
      ArgumentNullException: Scriptblock not found. Input to 'Throw' and 'Not Throw' must be enclosed in curly braces. (Parameter 'ActualValue')
      at Should-Throw, /home/vsts/work/_temp/TempModules/Pester/4.10.1/Functions/Assertions/PesterThrow.ps1: line 35
      at <ScriptBlock>, /home/vsts/work/1/s/test/GetInstalledPSResource/GetInstalledPSResource.Tests.ps1: line 157
 

[o-l-a-v]

Oops, I enclosed the test in scriptblock now @alerickson. 😊

[alerickson]

Thanks @o-l-a-v!