chore: Fix conversation status in webhooks (#3364)

- fix the wrong conversation status being sent in webhooks
- additional information in websocket events
- refactor activity messaging code
- move activity message generation to background job to stop the callback loop

spec/controllers/api/v1/accounts/conversations/assignments_controller_spec.rb

@@ -64,7 +64,10 @@ RSpec.describe 'Conversation Assignment API', type: :request do
 
         expect(response).to have_http_status(:success)
         expect(conversation.reload.assignee).to eq(nil)
-        expect(conversation.messages.last.content).to eq("Conversation unassigned by #{agent.name}")
+        expect(Conversations::ActivityMessageJob)
+          .to(have_been_enqueued.at_least(:once)
+        .with(conversation, { account_id: conversation.account_id, inbox_id: conversation.inbox_id, message_type: :activity,
+                              content: "Conversation unassigned by #{agent.name}" }))
       end
     end