feat(SegmentedControl): make listbox role to fix a11y

[bvandercar-vt]

Improves a11y of new SegmentedControl item

[adidahiya]

Various open source UI toolkits have different approaches for Segmented Control a11y:

• Primer explicitly advises against using radiogroup, tablist, or toolbar ARIA roles
• MUI's Toggle Button Group uses role="group"
• Mantine UI uses role="radiogroup"

Can you explain the motivations for your change and make an argument for setting the default as you've done in this PR?

I think a safer, better approach might be to add good documentation to the component docs suggesting that users should set their own ARIA role appropriately by specifying the role attribute.

[bvandercar-vt]

@adidahiya that is tricky. After reading through those, I definitely think my original choice of listbox was incorrect.

It sounds like radiogroup is the best option, I changed the code to that. Despite what the Primer link says, I see no evidence why it shouldn't be radiogroup when that's exactly how it behaves.

If you would like me to add a prop so that users can set the role manually (role?="group" | "list" | "radiogroup") and then we set the children roles and aria props based on that as well, I'm down. Otherwise, I don't think anyone would complain about it being radiogroup