fix(FormGroup): only place className on outer wrapper

[tw15egan]

Closes #4572

This ensures the className prop is only placed on the outer wrapper, and not duplicated. I've placed this behind a feature flag, but we may just want to go ahead and make this change as it would be difficult to style them independently as-is

Changelog

New

• Test story in FormGroup

Changed

• className prop is only placed on the outer wrapping fieldset element

Testing / Reviewing

Go to the test story and ensure the custom class is only placed on the outer wrapper

[netlify]

❌ Deploy Preview for carbon-react-next failed.

🔨 Explore the source changes: ad08cae

🔍 Inspect the deploy log: https://app.netlify.com/sites/carbon-react-next/deploys/613b3648648e14000891e768

[netlify]

✔️ Deploy Preview for carbon-elements ready!

🔨 Explore the source changes: ad08cae

🔍 Inspect the deploy log: https://app.netlify.com/sites/carbon-elements/deploys/613b3648256483000870cee7

😎 Browse the preview: https://deploy-preview-9526--carbon-elements.netlify.app

[netlify]

✔️ Deploy Preview for carbon-components-react ready!

🔨 Explore the source changes: ad08cae

🔍 Inspect the deploy log: https://app.netlify.com/sites/carbon-components-react/deploys/613b36489b94e60007be31d0

😎 Browse the preview: https://deploy-preview-9526--carbon-components-react.netlify.app

[tw15egan]

bump @joshblack when you have a chance 👍🏻

[joshblack]

Seems great! Quick question on the test stories, do we want those showing up in the production storybook or are you removing/disabling them before merge? 👀

[joshblack]

So sorry about the delay @tw15egan! Totally missed this 🤦

[tw15egan]

@joshblack will get rid of them before merging 🙂