bundles/smartd: ignore non-digit values in telegraf stats

bundles/smartd/files/telegraf_plugin

@@ -29,10 +29,16 @@ for device in devices:
 
         if 'nvme_smart_health_information_log' in json:
             for k, v in json['nvme_smart_health_information_log'].items():
+                if not str(v).isdigit():
+                    continue
+
                 telegraf_output.add(f'{k}={v}')
 
         if 'ata_smart_attributes' in json:
             for entry in json['ata_smart_attributes']['table']:
+                if not str(entry['raw']['value']).isdigit():
+                    continue
+
                 telegraf_output.add('{}={}'.format(
                     entry['name'],
                     entry['raw']['value'],