Upgrading flow and fixing lint errors

Summary:
Upgrading to flow 0.91, fixing a bunch of `$FloxFixMe`s that were introduced by upgrading to 0.86.
Also fixing some linting issues.

Reviewed By: priteshrnandgaonkar

Differential Revision: D13900794

fbshipit-source-id: 5d0a1b62371f3b5d34b909bae0876583acb6f977

src/ui/components/table/ManagedTable.js

@@ -156,9 +156,7 @@ class ManagedTable extends React.Component<
     shouldScrollToBottom: Boolean(this.props.stickyBottom),
   };
 
-  tableRef: {
-    current: null | List,
-  } = React.createRef();
+  tableRef = React.createRef<List>();
 
   scrollRef: {
     current: null | HTMLDivElement,