🐛 Stub out keyExtractor for EmptyVirtualizedList (#35)

* override keyExtractor for empty list

* update snapshots

* Remove keyExtractor from regular EmptyListView

Author: Jephuff

src/ImmutableVirtualizedList/EmptyVirtualizedList.js

@@ -77,6 +77,7 @@ class EmptyVirtualizedList extends PureComponent {
         renderItem={() => this.renderItem()}
         {...passThroughProps}
         immutableData={listData}
+        keyExtractor={() => 'empty'}
       />
     );
   }