Fix `<wa-radio>` hint styles OR remove the property/styles

[claviska]

From radio.md (not radio group):

I wasn't aware we added hint to individual radios. @lindsaym-fa is this something we want to support?

If so, we need to fix the styles for this example (it doesn't appear to be used elsewhere directly on <wa-radio>).

If not, moving the hint to the <wa-radio-group> and off the individual radios will solve it, but we'll also need to remove the property and any associated styles from <wa-radio>

To be clear, this is about hints on individual <wa-radio> items, NOT hints on <wa-radio-group> which we will continue to support.

[lindsaym-fa]

I had questioned this from the get-go. imo, we should not support hint on individual radios. Seems like a recipe for a mess.

[claviska]

Fixed in #1026