chore: update Dimensions API Flow types (facebook#31898)

Summary:
This small PR updates the Flow types used in Dimensions. The following changes has been made:
* generic types has been replaced with types from `NativeDeviceInfo` (which already were used in event subscription update)
* ~simplification of `DisplayMetricsAndroid` by spreading via intersection with `DisplayMetrics` type and removing shared properties~
  > I have tried both notations, but according to the lint, it looks like a Native Modules typing limitation which requires redundancy / code duplication in cases like this.

## Changelog

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[Internal] [Changed] - update Dimensions API Flow types

Pull Request resolved: facebook#31898

Test Plan: Running `yarn flow` in the workspace yields no errors.

Reviewed By: yungsters

Differential Revision: D29932940

Pulled By: GijsWeterings

fbshipit-source-id: bf97bb972964c585207e2450ccf71d932555e291

Libraries/Utilities/Dimensions.js

@@ -14,21 +14,16 @@ import EventEmitter, {
 import RCTDeviceEventEmitter from '../EventEmitter/RCTDeviceEventEmitter';
 import NativeDeviceInfo, {
   type DisplayMetrics,
+  type DisplayMetricsAndroid,
   type DimensionsPayload,
 } from './NativeDeviceInfo';
 import invariant from 'invariant';
 
-type DimensionsValue = {
-  window?: DisplayMetrics,
-  screen?: DisplayMetrics,
-  ...
-};
-
 const eventEmitter = new EventEmitter<{
-  change: [DimensionsValue],
+  change: [DimensionsPayload],
 }>();
 let dimensionsInitialized = false;
-let dimensions: DimensionsValue;
+let dimensions: DimensionsPayload;
 
 class Dimensions {
   /**
@@ -46,9 +41,9 @@ class Dimensions {
    * Example: `const {height, width} = Dimensions.get('window');`
    *
    * @param {string} dim Name of dimension as defined when calling `set`.
-   * @returns {Object?} Value for the dimension.
+   * @returns {DisplayMetrics? | DisplayMetricsAndroid?} Value for the dimension.
    */
-  static get(dim: string): Object {
+  static get(dim: string): DisplayMetrics | DisplayMetricsAndroid {
     invariant(dimensions[dim], 'No dimension set for key ' + dim);
     return dimensions[dim];
   }
@@ -57,9 +52,9 @@ class Dimensions {
    * This should only be called from native code by sending the
    * didUpdateDimensions event.
    *
-   * @param {object} dims Simple string-keyed object of dimensions to set
+   * @param {DimensionsPayload} dims Simple string-keyed object of dimensions to set
    */
-  static set(dims: $ReadOnly<{[key: string]: any, ...}>): void {
+  static set(dims: $ReadOnly<DimensionsPayload>): void {
     // We calculate the window dimensions in JS so that we don't encounter loss of
     // precision in transferring the dimensions (which could be non-integers) over
     // the bridge.
@@ -128,7 +123,7 @@ class Dimensions {
   }
 }
 
-let initialDims: ?$ReadOnly<{[key: string]: any, ...}> =
+let initialDims: ?$ReadOnly<DimensionsPayload> =
   global.nativeExtensions &&
   global.nativeExtensions.DeviceInfo &&
   global.nativeExtensions.DeviceInfo.Dimensions;

Libraries/Utilities/NativeDeviceInfo.js

@@ -11,7 +11,7 @@
 import type {TurboModule} from '../TurboModule/RCTExport';
 import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';
 
-type DisplayMetricsAndroid = {|
+export type DisplayMetricsAndroid = {|
   width: number,
   height: number,
   scale: number,

Libraries/Utilities/useWindowDimensions.js

@@ -9,10 +9,15 @@
  */
 
 import Dimensions from './Dimensions';
-import {type DisplayMetrics} from './NativeDeviceInfo';
+import {
+  type DisplayMetrics,
+  type DisplayMetricsAndroid,
+} from './NativeDeviceInfo';
 import {useEffect, useState} from 'react';
 
-export default function useWindowDimensions(): DisplayMetrics {
+export default function useWindowDimensions():
+  | DisplayMetrics
+  | DisplayMetricsAndroid {
   const [dimensions, setDimensions] = useState(() => Dimensions.get('window'));
   useEffect(() => {
     function handleChange({window}) {