applets/devicenotifier: add delay remove only for storage volumes

In !4580 (merged) I made a mistake by adding delay remove to all devices when it must be added only to storage volumes. This cause devices such mtp to not be removed for five seconds after device was unplugged. This MR fixes such things by checking if device is need to be delay removed (By adding delay only to storage volumes with valid storage drive parents). @fusionfuture