follow-up(ChatView) - align scroll button position with mobile clients

[Antreesy]

☑️ Resolves

• Follow-up from fix(styles): prevent typing indicator overlay #9826 (cc @dijeth )
• Scroll button was moved to the parent component level
• Its position updated based on NewMessage component's height (which is updated if someone is typing)

🖼️ Screenshots

🏚️ Before	🏡 After

🚧 Tasks

• Visual check / Testing
• Code review

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not required
• 📘 API documentation in docs/ has been updated or is not required
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required
• 🔖 Capability is added or not needed

[marcoambrosini]

I think the button should be within the boundaries of the message list, with 8px bottom margin to the new message form component

[Antreesy]

I think the button should be within the boundaries of the message list, with 8px bottom margin to the new message form component

You mean to lift it up on 8px, not lower? For now I restored it's initial position, so it will be a design change.
And as you came up with this suggestion, maybe we also should replace icon with double chevron, like on Android? https://pictogrammers.com/library/mdi/icon/chevron-double-down/

[marcoambrosini]

Icon change sounds good. I mean exactly like the screenshot you posted, ~ 8px above the newmessageform border.

[Antreesy]

/backport to stable27