[Messenger] Setting to have more minimalistic inbound Message Notification Indicator

Currently, when new inbound chat messages arrive via the Messenger widget, the notification pop-up displays previews of the latest chats and can expand to take up a large portion of the screen - sometimes reaching full height if there are multiple new messages.

We’d like an option for a more minimal notification experience, where instead of large pop-up chat previews, there’s a simple indicator (for example, a small badge or number on the chat widget icon) showing the count of unread or new messages.

This would help reduce distraction for users who are multitasking or working in other applications, while still allowing them to see that new activity has occurred.