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.

spec/factories/teams.rb

@@ -1,6 +1,6 @@
 FactoryBot.define do
   factory :team do
-    name { 'MyString' }
+    sequence(:name) { |n| "Team #{n}" }
     description { 'MyText' }
     allow_auto_assign { true }
     account