fix: provide accessible heading for components

[Antreesy]

☑️ Resolves

• Follow-up to fix(MediaSettings): provide accessible heading #12918
• Not a complete work
• For complex cases: add labelId

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

No visual changes

🚧 Tasks

• TODO:
• temporary apply :deep styles to NcModal (to adjust headings size)

🏁 Checklist

• 🌏 Tested with different browsers / clients:
  • Chromium (Chrome / Edge / Opera / Brave)
  • Firefox
  • Safari
  • Talk Desktop
  • Not risky to browser differences / client
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[Antreesy]

/backport to stable30