Silence the "The operation completed successfully" output when running Import-RegistryFile

[adbertram]

[corbob]

It would appear the simplest way to suppress this message would be to create a temporary file with New-TemporaryFile on PS5 and use the -RedirectStandardError flag on the Start-Process call.

Probably could create a similar function to create our own temporary file to backport this to PS3/4, or could test for New-TempFile and suppress for those that support the function.

"The operation completed successfully" is output to standard error (because clearly it's an error?)