Remove unused fixmes

Summary: Looks like some flow-disables were no longer necessary.

Reviewed By: jknoxville

Differential Revision: D9700398

fbshipit-source-id: 5514c16294624c1bed1d3818f9e271b07e320803

src/plugins/layout/index.js

@@ -28,7 +28,6 @@ import {
 import type {TrackType} from '../../fb-stubs/Logger.js';
 import SidebarExtensions from '../../fb-stubs/LayoutInspectorSidebarExtensions.js';
 
-// $FlowFixMe
 import debounce from 'lodash.debounce';
 
 export type InspectorState = {|