Automatic Windows MDM migration - Fleet 4.61.0

Fleet v4.61.0 now supports migrating Windows workstations from your old MDM solution without end-user interaction. Once migrated, you can enforce disk encryption, OS updates, and other custom OS settings to consolidate device management into a single, cross-platform MDM. GitHub issue: https://github.com/fleetdm/fleet/issues/22075 User story: As an IT admin, I want to migrate my Windows workstations from my old MDM solution to Fleet so that I can enforce disk encryption, OS updates, and other OS settings on these hosts. See other features released in Fleet 4.61.0: https://fleetdm.com/releases/fleet-4.61.0