Add lambdas to be able to add a Leading and Trailing composables into…

[wlmirand]

… Message List

🎯 Goal

Need to add a Custom composable that scrolls along with the Messages inside the MessageList component. I need one for Leading, to appear at the beginning of the conversation and one that appears at the end of the Conversation. Since these Composables rely on Data that are unrelated to the Stream Chat Data and also they need to be able to handle clicks, I could not achieve this by overriding ChatComponentFactory

🛠 Implementation details

Added two different composable lambdas with null default values that if they exists, they will be added as children of the LazyColumn.

🎨 UI Changes

🧪 Testing

Need to open the Conversation Screen and check if the Lambdas are properly rendered inside the LazyColumn

🎉 GIF