Fix redacted media thread showing "message removed" for every media item.

src/components/messages/messageMixin.js

@@ -279,6 +279,15 @@ export default {
       return false;
     },
 
+    redactedBySomeoneElse(event) {
+      if (!event.isRedacted()) return false;
+      const redactionEvent = event.getUnsigned().redacted_because;
+      if (redactionEvent) {
+        return redactionEvent.sender !== this.$matrix.currentUserId;
+      }
+      return false;
+    },
+
     formatTimeAgo(time) {
       const date = new Date();
       date.setTime(time);