hive: prefer injected job.Group over job.Registry
Except for some special cases it's preferred that modules depend on job.Group rather than job.Registry and creating a new job.Group from it via NewGroup. The reason is that the Cilium Hive integration provides a job.Group to modules that is already scoped (logger, pprof, ...) (https://github.com/cilium/cilium/blob/main/pkg/hive/hive.go#L157-L162).
Therefore, this commit changes the usages of job.Registry to use job.Group instead.
Related to: !42762 (hive: add metrics for hive jobs (total, errors, duration))