fix: index.esm.js is missing in npm package

[vvmnnnkv]

Description

js/dist/index.esm.js was missing from dist folder after installing threepio as dependency via npm. This was the reason syft.js's rollup build couldn't find and bundle threepio into syft.js.

Affected Dependencies

syft.js

How has this been tested?

Ran npm i && npm run build in syft.js

Checklist

• [x] I have followed the Contribution Guidelines and Code of Conduct
• [ ] I have commented my code following the OpenMined Styleguide
• [ ] I have labeled this PR with the relevant Type labels
• [ ] My changes are covered by tests

[sachin-101]

Fixes https://github.com/OpenMined/syft.js/issues/159