Fix "You might be interested in" flashing while searching in web UI (#16162)

app/javascript/mastodon/actions/search.js

@@ -32,6 +32,7 @@ export function submitSearch() {
     const value = getState().getIn(['search', 'value']);
 
     if (value.length === 0) {
+      dispatch(fetchSearchSuccess({ accounts: [], statuses: [], hashtags: [] }, ''));
       return;
     }