fix: Use `var` instead of `const` in demos/ready.js (#2343)
fix: Use `var` instead of `const` in demos/ready.js (#2343)

Safari 9.x and IE 10 do not support `const`, and `ready.js` is not transpiled to ES5.
material-components/material-components-web,material-components/material-components-web,material-components/material-components-web