fix(MessagesList): Stop fetching when reaching the chat beginning

[DorraJaouad]

☑️ Resolves

Old messages were fetched on every scroll event even though messages list weren't updated -> lost requests

Create a flag to stop fetching when :

• We reach system messages conversation_created and history_cleared
• For chats that don't have such, we wait another request and compare if in both times the list didn't change then we confirm that the very beginning of the chat was reached ( this case applies to chats that have expiration messages, and history cleared after setting it)

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

No visual changes just spinner doesn't show up when you scroll up at the top.

[nickvergessen]

For chats that don't have such, we wait another request and compare if in both times the list didn't change then we confirm that the very beginning of the chat was reached ( this case applies to chats that have expiration messages, and history cleared after setting it)

This can also happen when you have a full page of "hidden system messages" e.g. reactions only

[Antreesy]

Tested for these 3 cases, should be enough to cover, and don't break anything