fix(team): support team mentions on frontend

[Antreesy]

☑️ Resolves

• Ref Add ability to mention a team #12036
• Relevant, but not required: feat(mentions): allow teams to be mentioned #14204
• To test: uncomment $mention['type'] === 'team' || and && !str_starts_with($search, 'team/') in UserMention.php

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🏚️ Before	🏡 After

🚧 Tasks

• isCurrentUserTeam requires to be handled somehow with backend
• displayName is supposed to be passed from backend

🏁 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

[nickvergessen]

Tested and works

[nickvergessen]

/backport to stable31