[AND-182] Implement 'Create channel' flows in the compose sample app.

[VelikovPetar]

🎯 Goal

Implements the "Create channel" and "Create named group channel" flows in the Compose sample app.

Note: Follows the behaviour from the implementation from the XML sample almost identically (with some small UI adjustments)

🛠 Implementation details

• Implements AddChannelActivity as host activity for the "Create channel" flow
• Implements AddGroupChannelActivity as host activity for the "Create named group channel" flow
• Introduces filtering and custom event handling in ChannelsActivity to handle "draft" channels

🎨 UI Changes

Create channel	Create named group channel
create_chat.mp4	create_named_channel.mp4

🧪 Testing

1. Open compose sample app
2. Tap on the right toolbar icon
3. Create a channel OR:
4. Tap on the "Create a group" button to create a named group channel

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	3.04 MB	3.04 MB	0.00 MB	🟢
stream-chat-android-offline	3.25 MB	3.25 MB	0.00 MB	🟢
stream-chat-android-ui-components	7.91 MB	7.91 MB	0.00 MB	🟢
stream-chat-android-compose	9.04 MB	9.04 MB	0.00 MB	🟢