fix(GODT-2365): Use predictable remote ID for placeholder mailboxes

internal/user/user.go

@@ -191,11 +191,14 @@ func New(
 		user.syncAbort.Do(ctx, func(ctx context.Context) {
 			if user.vault.SyncStatus().IsComplete() {
 				user.log.Info("Sync already complete, only system label will be updated")
+
 				if err := user.syncSystemLabels(ctx); err != nil {
 					user.log.WithError(err).Error("Failed to update system labels")
 					return
 				}
+
 				user.log.Info("System label update complete, starting API event stream")
+
 				return
 			}