jobqueue/JobStatus: return result as json.RawMessage

Similarly to the recent changes to Dequeue(), let the caller unmarshal the
return JSON. This allows us to pass the result on without being able
to unmarshal it.

In follow-up patches, we will pass results of jobs to dependent jobs,
but the worker API does not know about the different job types, nor how
to unmarshal them.

internal/weldr/api.go

@@ -247,8 +247,10 @@ func (api *API) getComposeStatus(compose store.Compose) *composeStatus {
 	// All jobs are "osbuild" jobs.
 	var result worker.OSBuildJobResult
 
-	// is it ok to ignore this error?
-	jobStatus, _ := api.workers.JobStatus(jobId, &result)
+	jobStatus, _, err := api.workers.JobStatus(jobId, &result)
+	if err != nil {
+		panic(err)
+	}
 	return &composeStatus{
 		State:    composeStateFromJobStatus(jobStatus, &result),
 		Queued:   jobStatus.Queued,