fix: unattended count mismatch in report and list (#7263)

app/builders/v2/report_builder.rb

@@ -96,10 +96,9 @@ class V2::ReportBuilder
 
   def conversations
     @open_conversations = scope.conversations.where(account_id: @account.id).open
-    first_response_count = @account.reporting_events.where(name: 'first_response', conversation_id: @open_conversations.pluck('id')).count
     metric = {
       open: @open_conversations.count,
-      unattended: @open_conversations.count - first_response_count
+      unattended: @open_conversations.unattended.count
     }
     metric[:unassigned] = @open_conversations.unassigned.count if params[:type].equal?(:account)
     metric

app/finders/conversation_finder.rb

@@ -102,7 +102,7 @@ class ConversationFinder
     when 'participating'
       @conversations = current_user.participating_conversations.where(account_id: current_account.id)
     when 'unattended'
-      @conversations = @conversations.where(first_reply_created_at: nil)
+      @conversations = @conversations.unattended
     end
     @conversations
   end

app/models/conversation.rb

@@ -69,6 +69,7 @@ class Conversation < ApplicationRecord
   scope :unassigned, -> { where(assignee_id: nil) }
   scope :assigned, -> { where.not(assignee_id: nil) }
   scope :assigned_to, ->(agent) { where(assignee_id: agent.id) }
+  scope :unattended, -> { where(first_reply_created_at: nil) }
   scope :resolvable, lambda { |auto_resolve_duration|
     return none if auto_resolve_duration.to_i.zero?