Start-UnityEditor fails with unclear error when run with invalid Unity path

[jwittner]

You see this error:

Cannot convert the "System.Object[]" value of type "System.Object[]" to type "UnityInstance".
At C:\Users\jowitt\Documents\WindowsPowerShell\Modules\UnitySetup\1.4.29\UnitySetup.psm1:260 char:9
+         $Instance =  Get-UnitySetupInstance | Select-UnitySetupInstan ...
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : ConvertToFinalInvalidCastException

Could not find Unity Editor for version
At C:\Users\jowitt\Documents\WindowsPowerShell\Modules\UnitySetup\1.4.29\UnitySetup.psm1:270 char:9
+         throw "Could not find Unity Editor for version $version"
+         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (Could not find Unity Editor for version :String) [], RuntimeException
    + FullyQualifiedErrorId : Could not find Unity Editor for version