feat: Add new APIs for live reports with team filter (#10994)

This PR is part of the larger #10849 implementation and introduces a new
Live Reports API to provide real-time conversation metrics.

The /live_reports/conversation_metrics endpoint returns account-level or
team-level conversation statistics, including open, pending, unattended,
and unassigned conversation counts.

The /live_reports/grouped_conversation_metrics endpoint accepts a group
parameter, either team_id or assignee_id, and returns open and
unattended conversation counts based on the specified grouping.

config/routes.rb

@@ -337,6 +337,12 @@ Rails.application.routes.draw do
               get :bot_metrics
             end
           end
+          resources :live_reports, only: [] do
+            collection do
+              get :conversation_metrics
+              get :grouped_conversation_metrics
+            end
+          end
         end
       end
     end