Restores flow error suppression for [email protected] (facebookarchive#2014)

Summary:
**Summary**

Restores a flow error suppression annotation removed with D14074027

**Test Plan**

`yarn run flow`
No errors
Pull Request resolved: facebookarchive#2014

Reviewed By: dsainati1

Differential Revision: D14229161

Pulled By: dsainati1

fbshipit-source-id: b169d832d0b50e3366a94d53ae7e60ca89035ae7

Author: Claudio Procida

src/component/contents/DraftEditorContents-core.react.js

@@ -197,6 +197,7 @@ class DraftEditorContents extends React.Component<Props> {
           lastWrapperTemplate !== wrapperTemplate ||
           currentDepth === null ||
           depth > currentDepth;
+        // $FlowExpectedError joinClasses args in [email protected] are incorrect
         className = joinClasses(
           className,
           getListItemClasses(blockType, depth, shouldResetCount, direction),