chore: Refactor the notification service for participants (#6461)

app/models/concerns/message_filter_helpers.rb

@@ -9,6 +9,10 @@ module MessageFilterHelpers
     incoming? || outgoing?
   end
 
+  def notifiable?
+    incoming? || outgoing?
+  end
+
   def conversation_transcriptable?
     incoming? || outgoing?
   end

app/models/inbox.rb

@@ -106,6 +106,10 @@ class Inbox < ApplicationRecord
     channel_type == 'Channel::Whatsapp'
   end
 
+  def assignable_agents
+    (account.users.where(id: members.select(:user_id)) + account.administrators).uniq
+  end
+
   def active_bot?
     agent_bot_inbox&.active? || hooks.pluck(:app_id).include?('dialogflow')
   end