fix(NcReferenceWidget): set timeout to destroy idle widgets outside of viewports

[Antreesy]

☑️ Resolves

• Fix flickering widgets moving in an out of viewport (Talk chat)
  • When widget is out if view, a timer is set for 3 minutes (in case user scrolls back to it). If after timeout widget is still not visible, we destroy it, and it has to be rendered again
  • If widget is already rendered, we don't trigger the render method

🖼️ Screenshots

Sorry for bad sccreencast:
🏚️ Before - re-rendered each time

before.webm

🏡 After - re-rendered only if new or after 3 minutes

after.webm

🏁 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

[juliushaertl]

Thanks @Antreesy