Update typings for TypeScript 5.6

[jdanyow]

Fixes:

../../node_modules/jsep/typings/tsd.d.ts(179,2): error TS1203: 
Export assignment cannot be used when targeting ECMAScript 
modules. Consider using 'export default' or another module 
format instead.

[6utt3rfly]

@jdanyow - thank you for your PR and reporting the issue. The current possible usages of jsep include:

import jsep from '/PATH/TO/jsep.min.js';
import jsep from 'jsep';
import { Jsep } from 'jsep';
import * as jsep from 'jsep';
const jsep = require('jsep').default;
const { Jsep } = require('jsep');

I'm not sure if this proposed PR will work for all of these cases, since it's removing export = jsep. I'm reading that we may need to create a separate typings file for cjs and esm now?