NumberFlow does not work for older Safari versions

Minimal reproduction

https://stackblitz.com/edit/vitejs-vite-ec8hg3dz?file=index.html,src%2Fmain.ts

Describe the bug and the steps to reproduce it

For Safari 15.6.7 version, we are getting this error from the package.

this.attachInternals is not a function. (In 'this.attachInternals()', 'this.attachInternals' is undefined)