feat: add index to reporting events [CW-1960] (#7294)

* fix: annotation

* feat: add better index for reporting_events

db/migrate/20230612103936_add_index_to_reporting_events.rb

@@ -0,0 +1,7 @@
+class AddIndexToReportingEvents < ActiveRecord::Migration[7.0]
+  disable_ddl_transaction!
+
+  def change
+    add_index :reporting_events, [:account_id, :name, :created_at], name: 'reporting_events__account_id__name__created_at', algorithm: :concurrently
+  end
+end