fix(MessagesList): fix resizeObserver and scrolledToBottom state update

[Antreesy]

☑️ Resolves

• Follow-up to fix(MessagesList): keep chat at the bottom when list height is changing #14266
  • Keeps node reference for ResizeObserver after switching conversations
  • Ensure non-scrollable chat doesn't have 'scroll to bottom' button
• Fix Typing a message invokes the scroll indicator, and prevents the other party's next message from auto scrolling into view #14392 🚧
  • setChatScrolledToBottom(false) should be only set on scroll up (if we're scrolling down. it should be already set)

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🏡 After

2025-02-10_09h13_03.mp4

🔬 Test

• removing :key:
  • ResizeObserver works after conversation switch
  • nothing is broken, if we get rid of 'force-refresh' of whole component
• non-scrollable chats do not have 🔽 button:
  • on open (on open with focusing message)
  • on resize
  • on messages list (height) change
• scrollable chats do not have 🔽 button:
  • when scrolling down
  • when nothing to scroll
  • when new message arrives, and there's a mismatch of last read (follow-up from above)

🏁 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

[ShGKme]

Could you explain the change?

[Antreesy]

After swtiching to conversation, handleScroll is triggered. Regardless of container height, it sets value to false (whereas it shouldn't for non-scrollable chats)
For scrollable chats it also shouldn't set to false, when receiiving message (handleScroll is triggered with 'down' direction)

[DorraJaouad]

Sthg is wrong, chat is sticky when document is not focused and it scrolls to bottom ⚠️