Fix persistence for devices with UNKWN00000000xxxx serial number

[vcelarde]

• Replace randomly generated (UNKWN00000000xxxx) serial number for unknown devices (Default string, etc.) with a serial number generated by the unique device ID in the last element of the device path. This way the device will always get the same (unique) serial number and persistence will work correctly.
• Original version worked fine, but since serial number was randomly generated on each startup, persistence did not work and the persistence.conf file fills up with settings from all the randomly generated serial numbers over time.

[z3ntu]

Are you sure the serial numbers are consistent?

2024-04-04 21:20:53 | razer.device2                  | INFO     | Initialising device.2 RazerMambaElite
ERROR:root:random serial! 00031532006C0004

I unplugged and replugged the usb hub where my devices are connected and then the serial was different

2024-04-04 21:21:38 | razer.device2                  | INFO     | Initialising device.2 RazerMambaElite
ERROR:root:random serial! 00031532006C0010

("error" logging is added by me, diff attached)

diff --git a/daemon/openrazer_daemon/hardware/device_base.py b/daemon/openrazer_daemon/hardware/device_base.py
index 635f694b..fa332a01 100644
--- a/daemon/openrazer_daemon/hardware/device_base.py
+++ b/daemon/openrazer_daemon/hardware/device_base.py
@@ -974,8 +974,9 @@ class RazerDevice(DBusService):
                     time.sleep(0.1)
                     self.logger.debug('getting serial: {0} count:{1}'.format(serial, count))
 
-            if serial == '' or serial == 'Default string' or serial == 'empty (NULL)' or serial == 'As printed in the D cover':
-                serial = "".join([i for i in os.path.basename(self._device_path) if i.isalnum()])
+            #if serial == '' or serial == 'Default string' or serial == 'empty (NULL)' or serial == 'As printed in the D cover':
+            serial = "".join([i for i in os.path.basename(self._device_path) if i.isalnum()])
+            logging.error("random serial! " + str(serial))
 
             self._serial = serial.replace(' ', '_')