chore: Disable message hooks for conversations without incoming message (#7620)

When using client APIs to create conversations and auto-assignment is turned on, welcome messages were getting triggered. This PR disable the behaviour and ensure template hooks are triggered only if there are incoming messages present. 

Fixes: https://linear.app/chatwoot/issue/CW-2187

app/services/facebook/send_on_facebook_service.rb

@@ -60,11 +60,7 @@ class Facebook::SendOnFacebookService < Base::SendOnChannelService
 
   def sent_first_outgoing_message_after_24_hours?
     # we can send max 1 message after 24 hour window
-    conversation.messages.outgoing.where('id > ?', last_incoming_message.id).count == 1
-  end
-
-  def last_incoming_message
-    conversation.messages.incoming.last
+    conversation.messages.outgoing.where('id > ?', conversation.last_incoming_message.id).count == 1
   end
 
   def handle_facebook_error(exception)

app/services/instagram/send_on_instagram_service.rb

@@ -90,11 +90,7 @@ class Instagram::SendOnInstagramService < Base::SendOnChannelService
 
   def sent_first_outgoing_message_after_24_hours?
     # we can send max 1 message after 24 hour window
-    conversation.messages.outgoing.where('id > ?', last_incoming_message.id).count == 1
-  end
-
-  def last_incoming_message
-    conversation.messages.incoming.last
+    conversation.messages.outgoing.where('id > ?', conversation.last_incoming_message.id).count == 1
   end
 
   def config

app/services/message_templates/hook_execution_service.rb

@@ -3,6 +3,7 @@ class MessageTemplates::HookExecutionService
 
   def perform
     return if conversation.campaign.present?
+    return if conversation.last_incoming_message.blank?
 
     trigger_templates
   end