Fix `SetupInstallServicesFromInfSectionEx`.
- Call SetupDiSetDeviceRegistryPropertyW only if DeviceInfoSet is valid
- DeviceInfoSet can be INVALID_HANDLE_VALUE, treat this as NULL
- Improve function declaration
This moves the IExplore registration from cmd.exe (established in 4a4060ce3c (r52196) for CORE-1370) to syssetup.inf to avoid console popups on first boot.