Add push notifications to when a new message is sent to the user

[pranavrajs]

When an agent sends the message to the user, send a push notification to the user if the mobile app is in the background or closed.

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[HosAkh]

A notification sign on the chat FAB is essential for a seamless user experience. It allows users to minimize the chat and use the app with confidence, knowing that they will be notified when an agent responds. Moreover, if a user leaves the app (and are type that don't check or miss the email notification) they won’t see a red dot notification on the chat FAB the next time they log in, which could result in missed messages giving them the impression that we didn't care enough to respond or having a buggy app that doesn't show chat notification. Therefore, implementing this feature is crucial to ensure that users are promptly notified of any updates on their chat.

[umrashrf]

I achieved that by using Chatwoot's webhook (Conversation Updated) and sending the push notification from my nodejs server.