Printers: don't error on missing prtMarkerCounterUnit (librenms#17847)

* Printers: don't error on missing prtMarkerCounterUnit

* Update konica_c250i.json

Author: Jellyfrog

includes/discovery/sensors/count/printer.inc.php

@@ -22,7 +22,7 @@
         '.1.3.6.1.2.1.43.10.2.1.4.' . $index, // Printer-MIB::prtMarkerLifeCount.1.1
         'prtMarkerLifeCount',
         $device['os'],
-        'Life time ' . ($data['prtMarkerCounterUnit'] ?? null),
+        'Life time ' . ($data['prtMarkerCounterUnit'] ?? '?'),
         1,
         1,
         null,
@@ -39,7 +39,7 @@
         '.1.3.6.1.2.1.43.10.2.1.5.' . $index, // Printer-MIB::prtMarkerPowerOnCount.1.1
         'prtMarkerPowerOnCount',
         $device['os'],
-        ucfirst($data['prtMarkerCounterUnit'] ?? null) . ' since powered on',
+        ucfirst($data['prtMarkerCounterUnit'] ?? '?') . ' since powered on',
         1,
         1,
         null,

tests/data/konica_c250i.json

@@ -529,7 +529,7 @@
                     "sensor_oid": ".1.3.6.1.2.1.43.10.2.1.4.1.1",
                     "sensor_index": "prtMarkerLifeCount",
                     "sensor_type": "konica",
-                    "sensor_descr": "Life time ",
+                    "sensor_descr": "Life time ?",
                     "group": null,
                     "sensor_divisor": 1,
                     "sensor_multiplier": 1,
@@ -554,7 +554,7 @@
                     "sensor_oid": ".1.3.6.1.2.1.43.10.2.1.5.1.1",
                     "sensor_index": "prtMarkerPowerOnCount",
                     "sensor_type": "konica",
-                    "sensor_descr": " since powered on",
+                    "sensor_descr": "? since powered on",
                     "group": null,
                     "sensor_divisor": 1,
                     "sensor_multiplier": 1,
@@ -897,7 +897,7 @@
                     "sensor_oid": ".1.3.6.1.2.1.43.10.2.1.4.1.1",
                     "sensor_index": "prtMarkerLifeCount",
                     "sensor_type": "konica",
-                    "sensor_descr": "Life time ",
+                    "sensor_descr": "Life time ?",
                     "group": null,
                     "sensor_divisor": 1,
                     "sensor_multiplier": 1,
@@ -922,7 +922,7 @@
                     "sensor_oid": ".1.3.6.1.2.1.43.10.2.1.5.1.1",
                     "sensor_index": "prtMarkerPowerOnCount",
                     "sensor_type": "konica",
-                    "sensor_descr": " since powered on",
+                    "sensor_descr": "? since powered on",
                     "group": null,
                     "sensor_divisor": 1,
                     "sensor_multiplier": 1,