fix(NcActions): focus first checked item on open

[ShGKme]

☑️ Resolves

• Brings back fix: If a aria-selected button is present we focus on this one instead of the first entry #4678 after changes in the component
• aria-selected should be aria-checked
• aria-checked should not only present, but be 'true'
• aria-checked must be on the focusable element itself (otherwise there is an a11y issue)
• New possibility — check only radio buttons

IMO, this should happen only when ALL the buttons are one radio button group. But it is required even for heading in Text, where we have "Show outline" button together with heading radio buttons.

The solution is still not reliable, but I don't see any other simple solution...

🖼️ Screenshots

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 3️⃣ Backport to next requested with a Vue 3 upgrade

[ShGKme]

/backport to next

[emoral435]

Nice! :)