This PR fixes a bug where the task group information was not being set
on the serviceHook.AllocInfo struct, which is needed later on for calculating
the CheckID of a nomad service check. The CheckID is calculated independently
from multiple callsites, and the information being passed in must be consistent,
including the group name.
The workload.AllocInfo.Group was not set at this callsite, due to the bug fixed in this PR.
https://github.com/hashicorp/nomad/blob/main/client/serviceregistration/nsd/nsd.go#L114
