Merge pull request #3811 from ngraziano/monitor-no-heating-bed

Correct the test to hide bed temperature when no heated bed is present.

resources/qml/PrintMonitor.qml

@@ -67,7 +67,7 @@ Column
     HeatedBedBox
     {
         visible: {
-            if(activePrinter != null && activePrinter.bed_temperature != -1)
+            if(activePrinter != null && activePrinter.bedTemperature != -1)
             {
                 return true
             }