feat: better download for conversation traffic heatmap (#6755)

* feat: genearte report in a grid

* refactor: update API usage

* refactor: separate generate method

* refactor: abstract transform_data

* feat: annotate with comments

* feat: add explicit timezone

* feat: download data only in user timezone

* fix: dates included in heatmap

app/controllers/api/v2/accounts/reports_controller.rb

@@ -1,5 +1,7 @@
 class Api::V2::Accounts::ReportsController < Api::V1::Accounts::BaseController
   include Api::V2::Accounts::ReportsHelper
+  include Api::V2::Accounts::HeatmapHelper
+
   before_action :check_authorization
 
   def index
@@ -34,6 +36,9 @@ class Api::V2::Accounts::ReportsController < Api::V1::Accounts::BaseController
 
   def conversation_traffic
     @report_data = generate_conversations_heatmap_report
+    timezone_offset = (params[:timezone_offset] || 0).to_f
+    @timezone = ActiveSupport::TimeZone[timezone_offset]
+
     generate_csv('conversation_traffic_reports', 'api/v2/accounts/reports/conversation_traffic')
   end