udev: cancel reset if modem is already back

Cancel reset if modem is back before reset sequence is started. When upgrading the modem through fwupd, it will enter fastboot. Therefore, it disappears from the USB bus for a few ms. However, the eg25-manager considers this as an issue and resets the modem a bit later during the upgrade process. To avoid this, cancel the reset sequence if the modem is already back before the reset sequence is started. This will take less than 3 seconds.