Fix MatrixClientPeg imports

src/Notifier.js

@@ -16,7 +16,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import MatrixClientPeg from './MatrixClientPeg';
+import {MatrixClientPeg} from './MatrixClientPeg';
 import PlatformPeg from './PlatformPeg';
 import * as TextForEvent from './TextForEvent';
 import Analytics from './Analytics';