Align useAnimatedValue with OSS types (#49643)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49643

## Motivation
Modernising the RN codebase to allow for modern Flow tooling to process it.

## This diff
Aligns `useAnimatedValue.js` with its manual .d.ts types.

Changelog: [Internal]

Reviewed By: huntie

Differential Revision: D70096210

fbshipit-source-id: c3cd517eccf1cb68400772ddde6e5891861c927d