Detect backend support for announcements

src/components/side_drawer/side_drawer.js

@@ -95,7 +95,8 @@ const SideDrawer = {
       }
     },
     ...mapState({
-      pleromaChatMessagesAvailable: state => state.instance.pleromaChatMessagesAvailable
+      pleromaChatMessagesAvailable: state => state.instance.pleromaChatMessagesAvailable,
+      supportsAnnouncements: state => state.announcements.supportsAnnouncements
     }),
     ...mapGetters(['unreadChatCount', 'unreadAnnouncementCount'])
   },

src/components/side_drawer/side_drawer.vue

@@ -192,6 +192,7 @@
           </a>
         </li>
         <li
+          v-if="currentUser && supportsAnnouncements"
           @click="toggleDrawer"
         >
           <router-link