Fix signal loop in graceful manager (#19943)

modules/graceful/manager_unix.go

@@ -157,6 +157,7 @@ func (g *Manager) handleSignals(ctx context.Context) {
 		case <-ctx.Done():
 			log.Warn("PID: %d. Background context for manager closed - %v - Shutting down...", pid, ctx.Err())
 			g.DoGracefulShutdown()
+			return
 		}
 	}
 }