feat: Create campaign conversation only if user interacts with the bubble (#2335)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/views/api/v1/widget/campaigns/index.json.jbuilder

@@ -1,4 +1,6 @@
 json.array! @campaigns do |campaign|
   json.id campaign.display_id
   json.trigger_rules campaign.trigger_rules
+  json.message campaign.message
+  json.sender campaign.sender&.slice(:name, :avatar_url)
 end