Start-AzsDiskMigrationJob doesn't validate disks on run

As per process on https://docs.microsoft.com/en-us/azure-stack/operator/azure-stack-manage-storage-shares?view=azs-2108#to-migrate-managed-disks-using-powershell end users are required to create a get-azsdisk object when moving disks. Upon running the disk migration cmdlet seems to take what's in the object at face value up to and including refusing to migrate a disk due to it being "Attached" even though the disk was detached prior to making an object with the appropriate disks to move via get-azsdisk.
Expected behavior should fall in line with other PowerShell cmdlets in validating the data on run rather than assuming the arbitrary data from a cast object is correct in order to prevent issues due to stale data.

Start with Start-AzsDiskMigrationJob and the Get-AzSDisk object flow described in the issue. Reproduce migration with disk data that became stale after object creation, then verify the cmdlet validates current disk state at execution time and handles detached disks correctly.

Written by the indexing model from the issue text.