[drawer] Default <Radio.Root> span gets ignored within <Drawer>

# Docs feedback

## How can we improve Base UI documentation?

I ran into a scenario where I'm using the Radio component inside of a Drawer and I couldn't click on the radio buttons. A good number of tokens later and my agents realized it was related to the swipe behavior of the Drawer not ignoring the default `` elements used. Swapping the default rendering element to a button fixed it.

```ts
// useSwipeDismiss.ts

const DEFAULT_IGNORE_SELECTOR = 'button,a,input,select,textarea,label,[role="button"]';
```

I'm probably dumb and just didn't think to check there first, but might be worthwhile to call this out somewhere perhaps

Start by reading useSwipeDismiss.ts, especially DEFAULT_IGNORE_SELECTOR, and confirm why the default span rendered by Radio.Root is not ignored during Drawer swipe handling. Add a Drawer documentation note describing the interaction and the button-rendering workaround, then verify that the guidance clearly explains how to make the radio buttons clickable.

Written by the indexing model from the issue text.