no log: Fix a issue that a non-serialize object is used in redux reducers

frontend/src/@redux/reducers/site.ts

@@ -24,7 +24,7 @@ interface Site {
   progress: Site.Progress[];
   notifier: {
     content: string | null;
-    update: Date;
+    timestamp: string;
   };
   notifications: Server.Notification[];
   sidebar: string;
@@ -37,7 +37,7 @@ const defaultSite: Site = {
   progress: [],
   notifier: {
     content: null,
-    update: new Date(),
+    timestamp: String(Date.now),
   },
   notifications: [],
   sidebar: "",
@@ -111,7 +111,7 @@ const reducer = createReducer(defaultSite, (builder) => {
 
   builder.addCase(siteUpdateNotifier, (state, action) => {
     state.notifier.content = action.payload;
-    state.notifier.update = new Date();
+    state.notifier.timestamp = String(Date.now);
   });
 
   builder

frontend/src/App/Notification.tsx

@@ -154,7 +154,7 @@ const NotificationCenter: FunctionComponent = () => {
     if (notifier.content) {
       setTooltip(true);
     }
-  }, [notifier.update]);
+  }, [notifier.timestamp]);
 
   return (
     <React.Fragment>