feat(message-center): Update types

Author: loonskai

src/features/message-center/components/MessageCenter.js

@@ -16,7 +16,7 @@ import Internationalize from '../../../elements/common/Internationalize';
 
 type Props = {|
     apiHost: string,
-    buttonComponent: React.ComponentType<{ render: () => React.Node }>,
+    buttonComponent: React.ComponentType<{ render: () => React.Node, badgeCount: null | number }>,
     contentPreviewProps?: ContentPreviewProps,
     getEligibleMessages: () => Promise<GetEligibleMessageCenterMessages>,
     getToken: (fileId: string) => Promise<Token>,