Fix: Add VehicleSync::UpdateData to vehicle entity

[Deewarz]

I accidentally removed the addition of VehicleSync::UpdateData on the vehicle entity

a2e42f7#diff-9da33544966d1e2c2602e3066a4cd1a10ea0c7f81bb799e45ba69ca74638d94dL51

As explained by @zpl-zak we need it:

ensure() call does both add the component and retrieve a reference
otherwise the entity has incomplete data and can not be considered a valid Vehicle
we will eventually start using ecs prefabs, so it becomes more obvious what components the entities consist of, but for now we just attach components as we go