Flow: make more objects exact (#27790)

Summary:
Changelog: [Internal]

This makes a couple objects more exact. Nothing critical, just noticed
this old branch I had created when doing some Flow upgrades in the past.

DiffTrain build for commit facebook/react@f498aa2.

Reviewed By: hoxyq

Differential Revision: D51824015

Pulled By: hoxyq

packages/react-native/Libraries/Renderer/shims/ReactNativeViewConfigRegistry.js

@@ -7,7 +7,7 @@
  * @noformat
  * @flow strict-local
  * @nolint
- * @generated SignedSource<<3cf9b746913da1666cb5bce0ae12d978>>
+ * @generated SignedSource<<73af5b3fe29d226634ed64bc861634df>>
  */
 
 'use strict';
@@ -24,13 +24,11 @@ export const customBubblingEventTypes: {
       skipBubbling?: ?boolean,
     }>,
   }>,
-  ...
 } = {};
 export const customDirectEventTypes: {
   [eventName: string]: $ReadOnly<{
     registrationName: string,
   }>,
-  ...
 } = {};
 
 const viewConfigCallbacks = new Map<string, ?() => ViewConfig>();