Clear announcement history using window.clearLastViewedAnnouncement()

This helps testing, and can be eventually removed. No harm leaving it there, though.

ui/component/app/index.js

@@ -7,6 +7,7 @@ import {
   selectSyncIsLocked,
 } from 'redux/selectors/sync';
 import { doUserSetReferrer } from 'redux/actions/user';
+import { doSetLastViewedAnnouncement } from 'redux/actions/content';
 import {
   selectOdyseeMembershipIsPremiumPlus,
   selectUser,
@@ -58,6 +59,7 @@ const perform = {
   fetchModBlockedList: doFetchModBlockedList,
   fetchModAmIList: doFetchCommentModAmIList,
   doOpenAnnouncements,
+  doSetLastViewedAnnouncement,
 };
 
 export default hot(connect(select, perform)(App));

ui/component/app/view.jsx

@@ -89,6 +89,7 @@ type Props = {
   fetchModAmIList: () => void,
   homepageFetched: boolean,
   doOpenAnnouncements: () => void,
+  doSetLastViewedAnnouncement: (hash: string) => void,
 };
 
 function App(props: Props) {
@@ -123,6 +124,7 @@ function App(props: Props) {
     fetchModAmIList,
     homepageFetched,
     doOpenAnnouncements,
+    doSetLastViewedAnnouncement,
   } = props;
 
   const isMobile = useIsMobile();
@@ -481,6 +483,13 @@ function App(props: Props) {
     }
   }, [prefsReady]);
 
+  useEffect(() => {
+    window.clearLastViewedAnnouncement = () => {
+      console.log('Clearing history. Please wait ...');
+      doSetLastViewedAnnouncement('');
+    };
+  }, []);
+
   // Keep this at the end to ensure initial setup effects are run first
   useEffect(() => {
     if (!hasSignedIn && hasVerifiedEmail) {