[MM-56616] Changes for the DM for batch reporting (#26019)

* [MM-56616] Changes for the DM for batch reporting

* Use requesting user's locale

* Fix lint

* Remove unnecessary test

* Move back to file attachment

* Add default API case

* Fix i18n

* Hardcode the CSV string

server/public/model/report.go

@@ -12,6 +12,7 @@ import (
 )
 
 const (
+	ReportDurationAllTime       = "all_time"
 	ReportDurationLast30Days    = "last_30_days"
 	ReportDurationPreviousMonth = "previous_month"
 	ReportDurationLast6Months   = "last_6_months"