Fix prototype check in AnimatedObject.js

[maman]

Summary:

isPlainObject function defined in AnimatedObject.js doesn't handle Object.create(null) correctly.

this will throws when encountering objects with null prototype:

Object.getPrototypeOf(Object.create(null)).isPrototypeOf(Object)
// TypeError: Cannot read properties of null (reading 'isPrototypeOf')

This breaks compatibility with libraries that use Object.create(null) for creating clean dictionary objects.

Changelog:

[GENERAL] [FIXED] - Handle Object.create(null) correctly in AnimatedObject.js' isPlainObject function

Test Plan:

import { isPlainObject } from 'react-native/Libraries/Animated/nodes/AnimatedObject';

// Before: throws TypeError
// After: returns true
isPlainObject(Object.create(null));

// Existing behavior unchanged
isPlainObject({});           // true
isPlainObject([]);           // false
isPlainObject(null);         // false
isPlainObject(new Date());   // false

[javache]

The value !== null and typeof checks are duplicated here. Can we simplify this?

[maman]

done. simplified the checks, and adds early return for non-object scenario

[maman]

got this comment: #54820 (comment), but I didn't change the return type / any of RN public js api 🤔

manually running the diff-api-snapshot script returns NON_BREAKING rather than BREAKING:

codespace:/workspaces/react-native> git show 9fb2eb517ae017629a1e43bad729068df87780ac:packages/react-native/ReactNativeApi.d.ts
 > ReactNativeApi-after.d.ts
codespace:/workspaces/react-native> node ./scripts/js-api/diff-api-snapshot packages/react-native/ReactNativeApi.d.ts ReactNati
veApi-after.d.ts
{
  "result": "NON_BREAKING",
  "changedApis": []
}

is there anything missing from my side?

[react-native-bot]

	Warnings
⚠️	❗ JavaScript API change detected - This PR commits an update to ReactNativeApi.d.ts, indicating a change to React Native's public JavaScript API. Please include a clear changelog message. This change will be subject to extra review. This change was flagged as: BREAKING

Generated by 🚫 dangerJS against 9fb2eb5

[meta-codesync]

@zeyap has imported this pull request. If you are a Meta employee, you can view this in D88754908.

[meta-codesync]

@javache merged this pull request in 4e0b923.

[react-native-bot]

This pull request was successfully merged by @maman in 4e0b923

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