VM Snapshot stuck at Expunging with KvmFileBasedStorageVmSnapshotStrategy

### problem

`KvmFileBasedStorageVmSnapshotStrategy.deleteVMSnapshot` transitions the VM snapshot to `Expunging` during delete but doesn't transition it to `Error` state in case of exception or timeout

`VMSnapshotManagerImpl.hasActiveVMSnapshotTasks` counts `Expunging` as work in
progress, so operations like reboot and snapshot operations are blocked.

### versions

4.22

### The steps to reproduce the bug

1. Take a disk-only VM snapshot.
2. Write lots of data to the VM
3. set commands.timeout=MergeDiskOnlyVmSnapshotCommand=20
4. Delete the snapshot.

...

### What to do about it?

Snapshot state should transition to Error in case of timeout

Comienza con KvmFileBasedStorageVmSnapshotStrategy.deleteVMSnapshot y VMSnapshotManagerImpl.hasActiveVMSnapshotTasks, y luego reproduce la eliminación de un snapshot solo de disco con commands.timeout=MergeDiskOnlyVmSnapshotCommand=20. Sigue la ruta del timeout o de la excepción y verifica que el snapshot alcance Error en lugar de permanecer en Expunging, para que los reinicios y las operaciones de snapshot posteriores ya no queden bloqueados.

Escrito por el modelo de indexación a partir del texto del issue.