[vue3] fix: fix unmount issues and call reactivity

[Antreesy]

☑️ Resolves

• Reactivity doesn't work correctly for callParticipantModels, this leads to missed updates / re-renders, which worked in Vue2

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🚧 Tasks

• replace ref with reactive
  • ⚠️ doesn't work deeply (or works, but flacky), if we push models later in the reactive array, and then update some properties null -> object (stream, peer, speaking)
• Minor TypeErrors in console.log
• Participant join with video
• Participant join with screenshare (don't see)
• Participant and speaking indicator (don't see)
• Participant stops screenshare (main peer video is missing for several seconds)

🏁 Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences
• 🖥️ Tested with Desktop client or should not be risky for it
• 🖌️ 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