[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/post.go

@@ -52,7 +52,6 @@ const (
 	PostTypeMe                     = "me"
 	PostCustomTypePrefix           = "custom_"
 	PostTypeReminder               = "reminder"
-	PostTypeAdminReport            = "system_admin_report"
 
 	PostFileidsMaxRunes   = 300
 	PostFilenamesMaxRunes = 4000
@@ -451,8 +450,7 @@ func (o *Post) IsValid(maxPostSize int) *AppError {
 		PostTypeReminder,
 		PostTypeMe,
 		PostTypeWrangler,
-		PostTypeGMConvertedToChannel,
-		PostTypeAdminReport:
+		PostTypeGMConvertedToChannel:
 	default:
 		if !strings.HasPrefix(o.Type, PostCustomTypePrefix) {
 			return NewAppError("Post.IsValid", "model.post.is_valid.type.app_error", nil, "id="+o.Type, http.StatusBadRequest)

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"