worker: log error details on job failure

Currently errors like clienterror 28 ("at least one target failed") have
all the relevant information in the details, don't omit these details
from the worker logs.

cmd/osbuild-worker/jobimpl-osbuild.go

@@ -170,6 +170,9 @@ func validateResult(result *worker.OSBuildJobResult, jobID string) {
 	logWithId := logrus.WithField("jobId", jobID)
 	if result.JobError != nil {
 		logWithId.Errorf("osbuild job failed: %s", result.JobError.Reason)
+		if result.JobError.Details != nil {
+			logWithId.Errorf("failure details : %v", result.JobError.Details)
+		}
 		return
 	}
 	// if the job failed, but the JobError is