Refactor IntersectionObserver, MutationObserver and PerformanceObserver options as interfaces (facebook#49737)

Summary:
Pull Request resolved: facebook#49737

Changelog: [internal]

Just a minor change to align with similar other option bags and TypeScript definitions.

Reviewed By: huntie

Differential Revision: D70355669

fbshipit-source-id: 37c44338c7b358eb2d25e8a14c75a78545b34bf1

Author: rubennorte

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -9460,10 +9460,10 @@ exports[`public API should not change unintentionally src/private/webapis/inters
   entries: Array<IntersectionObserverEntry>,
   observer: IntersectionObserver
 ) => mixed;
-type IntersectionObserverInit = {
-  threshold?: number | $ReadOnlyArray<number>,
-  rnRootThreshold?: number | $ReadOnlyArray<number>,
-};
+export interface IntersectionObserverInit {
+  threshold?: number | $ReadOnlyArray<number>;
+  rnRootThreshold?: number | $ReadOnlyArray<number>;
+}
 declare export default class IntersectionObserver {
   constructor(
     callback: IntersectionObserverCallback,
@@ -9507,15 +9507,15 @@ exports[`public API should not change unintentionally src/private/webapis/mutati
   mutationRecords: $ReadOnlyArray<MutationRecord>,
   observer: MutationObserver
 ) => mixed;
-type MutationObserverInit = $ReadOnly<{
-  subtree?: boolean,
-  childList: true,
-  attributes?: boolean,
-  attributeFilter?: $ReadOnlyArray<string>,
-  attributeOldValue?: boolean,
-  characterData?: boolean,
-  characterDataOldValue?: boolean,
-}>;
+export interface MutationObserverInit {
+  +subtree?: boolean;
+  +childList: true;
+  +attributes?: boolean;
+  +attributeFilter?: $ReadOnlyArray<string>;
+  +attributeOldValue?: boolean;
+  +characterData?: boolean;
+  +characterDataOldValue?: boolean;
+}
 declare export default class MutationObserver {
   constructor(callback: MutationObserverCallback): void;
   observe(target: ReactNativeElement, options?: MutationObserverInit): void;
@@ -9687,12 +9687,12 @@ export type PerformanceObserverCallback = (
   observer: PerformanceObserver,
   options?: PerformanceObserverCallbackOptions
 ) => void;
-export type PerformanceObserverInit = {
-  entryTypes?: Array<PerformanceEntryType>,
-  type?: PerformanceEntryType,
-  buffered?: boolean,
-  durationThreshold?: DOMHighResTimeStamp,
-};
+export interface PerformanceObserverInit {
+  +entryTypes?: Array<PerformanceEntryType>;
+  +type?: PerformanceEntryType;
+  +buffered?: boolean;
+  +durationThreshold?: DOMHighResTimeStamp;
+}
 declare export class PerformanceObserver {
   constructor(callback: PerformanceObserverCallback): void;
   observe(options: PerformanceObserverInit): void;

packages/react-native/src/private/webapis/intersectionobserver/IntersectionObserver.js

@@ -21,10 +21,10 @@ export type IntersectionObserverCallback = (
   observer: IntersectionObserver,
 ) => mixed;
 
-type IntersectionObserverInit = {
+export interface IntersectionObserverInit {
   // root?: ReactNativeElement, // This option exists on the Web but it's not currently supported in React Native.
   // rootMargin?: string, // This option exists on the Web but it's not currently supported in React Native.
-  threshold?: number | $ReadOnlyArray<number>,
+  threshold?: number | $ReadOnlyArray<number>;
 
   /**
    * This is a React Native specific option (not spec compliant) that specifies
@@ -36,8 +36,8 @@ type IntersectionObserverInit = {
    * Note: If `rnRootThreshold` is set, and `threshold` is not set,
    * `threshold` will not default to [0] (as per spec)
    */
-  rnRootThreshold?: number | $ReadOnlyArray<number>,
-};
+  rnRootThreshold?: number | $ReadOnlyArray<number>;
+}
 
 /**
  * The [Intersection Observer API](https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API)

packages/react-native/src/private/webapis/mutationobserver/MutationObserver.js

@@ -21,18 +21,18 @@ export type MutationObserverCallback = (
   observer: MutationObserver,
 ) => mixed;
 
-type MutationObserverInit = $ReadOnly<{
-  subtree?: boolean,
+export interface MutationObserverInit {
+  +subtree?: boolean;
   // This is the only supported option so it's required to be `true`.
-  childList: true,
+  +childList: true;
 
   // Unsupported:
-  attributes?: boolean,
-  attributeFilter?: $ReadOnlyArray<string>,
-  attributeOldValue?: boolean,
-  characterData?: boolean,
-  characterDataOldValue?: boolean,
-}>;
+  +attributes?: boolean;
+  +attributeFilter?: $ReadOnlyArray<string>;
+  +attributeOldValue?: boolean;
+  +characterData?: boolean;
+  +characterDataOldValue?: boolean;
+}
 
 /**
  * This is a React Native implementation for the `MutationObserver` API

packages/react-native/src/private/webapis/performance/PerformanceObserver.js

@@ -66,12 +66,12 @@ export type PerformanceObserverCallback = (
   options?: PerformanceObserverCallbackOptions,
 ) => void;
 
-export type PerformanceObserverInit = {
-  entryTypes?: Array<PerformanceEntryType>,
-  type?: PerformanceEntryType,
-  buffered?: boolean,
-  durationThreshold?: DOMHighResTimeStamp,
-};
+export interface PerformanceObserverInit {
+  +entryTypes?: Array<PerformanceEntryType>;
+  +type?: PerformanceEntryType;
+  +buffered?: boolean;
+  +durationThreshold?: DOMHighResTimeStamp;
+}
 
 function getSupportedPerformanceEntryTypes(): $ReadOnlyArray<PerformanceEntryType> {
   if (!NativePerformance) {