Don't swallow error.

src/ContentMessages.js

@@ -278,6 +278,7 @@ class ContentMessages {
     sendStickerContentToRoom(url, roomId, info, text, matrixClient) {
         return MatrixClientPeg.get().sendStickerMessage(roomId, url, info, text).catch((e) => {
             console.warn(`Failed to send content with URL ${url} to room ${roomId}`, e);
+            throw e;
         });
     }