fix(website): no longer depend on the legacy custom-elements json file

[bdryanovski]

Website no longer depends on the custom-elements.legacy.json file that we generate.

At the moment the legacy file is used for generating control knobs for the Storybook.

To fully remove the dependency and the need of generating the legacy file we need to wait for a new package for @web/storybook-prebuild

Right now the @web/storybook-prebuilt@0.1.25 that is the latest stable release is not compatible with the new custom elements format. It comes with prebuild Storybook 6.3.7~ - we require 6.4.0~ -

The alpha version of @web/storybook-prebuilt@0.1.26.alpha.1 comes with 6.4.0-alpha.33. But because is alpha (unstable) release I prefer to wait a little longer before updating the packages. The estimated release for stable 6.4.0 is (2021-09-20) so I suspect by the end of September we could update the Storybook prebuild package.

The update of the Storybook will resolve these issues:

• No longer we will need to generate custom-elements.legacy.json file
• All dependencies for generating the file could be removed
• Storybook Knobs/Controls will include all possible fields for web components that come from the parent class.

Storybook 6.4.0 Release notes