Return full SPN data when CheckMgmt is used

[missing0x00]

Removes the Select-Object commands from the Get-SQLInstanceDomain -CheckMgmt results.

These cause all other properties to be removed, losing valuable info such as SPN and DomainAccount.

NOTE: I have not tested this in an environment that actually has MSServerClusterMgmtAPI SPNs configured. I wouldn't anticipate this causing any issues, but could potentially use some testing.