Extend ColorValue Flow type to include numbers

Summary:
Adds `number` to the `ColorValue` union type.

Per our docs, React Native supports specifying colours as RGBA values packed into ints: https://reactnative.dev/docs/colors#color-ints. It looks like this case was missed in D6226807 (da04796) when we started typing the `StyleSheet` API with Flow.

Changelog: [General][Fixed] - Support numeric color values in StyleSheet's Flow types

Reviewed By: yungsters

Differential Revision: D34140748

fbshipit-source-id: 5bfe2995a473260926fa3c8b6926bb841615d393

Author: motiz88

Libraries/StyleSheet/StyleSheetTypes.js

@@ -14,7 +14,7 @@ const AnimatedNode = require('../Animated/nodes/AnimatedNode');
 
 import type {NativeColorValue} from './PlatformColorValueTypes';
 
-export type ____ColorValue_Internal = null | string | NativeColorValue;
+export type ____ColorValue_Internal = null | string | number | NativeColorValue;
 
 export type ColorArrayValue = null | $ReadOnlyArray<____ColorValue_Internal>;
 export type PointValue = {|