feat: Add the support for custom attributes in message variables (#8511)

app/drops/contact_drop.rb

@@ -18,4 +18,9 @@ class ContactDrop < BaseDrop
   def last_name
     @obj.try(:name).try(:split).try(:last).try(:capitalize) if @obj.try(:name).try(:split).try(:size) > 1
   end
+
+  def custom_attribute
+    custom_attributes = @obj.try(:custom_attributes) || {}
+    custom_attributes.transform_keys(&:to_s)
+  end
 end

app/drops/conversation_drop.rb

@@ -19,6 +19,11 @@ class ConversationDrop < BaseDrop
     end
   end
 
+  def custom_attribute
+    custom_attributes = @obj.try(:custom_attributes) || {}
+    custom_attributes.transform_keys(&:to_s)
+  end
+
   private
 
   def message_sender_name(sender)