Update chat app to a better showcasable UI/UX

[sacOO7]

• I’ve been exploring ready-to-use online UI chat SDKs that can be integrated with our Kotlin SDK.
• The goal is to enhance the user interface (UI) and user experience (UX), and potentially introduce features that showcase Ably’s chat capabilities. This includes aiming for a cleaner, more visually appealing design, improved load times, and intuitive navigation.
• One Jetpack Compose-based app that stood out is Jetchat, this is chat sample app provided by google itself.
• It looks like we could integrate our components with it to work with Ably, and potentially feature this setup in our web documentation.

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