Make more of the codebase conform to strict types (#10857)

src/Notifier.ts

@@ -132,7 +132,7 @@ class NotifierClass {
         let msg = this.notificationMessageForEvent(ev);
         if (!msg) return;
 
-        let title;
+        let title: string | undefined;
         if (!ev.sender || room.name === ev.sender.name) {
             title = room.name;
             // notificationMessageForEvent includes sender, but we already have the sender here
@@ -153,6 +153,8 @@ class NotifierClass {
             }
         }
 
+        if (!title) return;
+
         if (!this.isBodyEnabled()) {
             msg = "";
         }