fix(zero): fix waiting for random time while rate limiting (#8656)

Fixes dgraph-io/projects-internal#87

dgraph/cmd/zero/assign.go

@@ -208,7 +208,7 @@ func (s *Server) AssignIds(ctx context.Context, num *pb.Num) (*pb.AssignedIds, e
 			// Return error after random delay.
 			//nolint:gosec // random generator in closed set does not require cryptographic precision
 			delay := rand.Intn(int(opts.limiterConfig.RefillAfter))
-			time.Sleep(time.Duration(delay) * time.Second)
+			time.Sleep(time.Duration(delay))
 			return errors.Errorf("Cannot lease UID because UID lease for the namespace %#x is "+
 				"exhausted. Please retry after some time.", ns)
 		}