Divide TrialEnd date by 1000 to account for it being in ms (#20173)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/cloud.go

@@ -53,7 +53,8 @@ func (a *App) SendUpgradeConfirmationEmail() *model.AppError {
 	}
 
 	// Build readable trial end date
-	endTimeStamp := subscription.TrialEndAt
+	// Trial end is passed as unix timestamp in ms
+	endTimeStamp := subscription.TrialEndAt / 1000
 	t := time.Unix(endTimeStamp, 0)
 	trialEndDate := fmt.Sprintf("%s %d, %d", t.Month(), t.Day(), t.Year())