Fix QML errors due to property providers not being initialised yet

This then updates in a fraction of a millisecond later before things even appear on the screen, so it's not so bad to not have a tooltip or to have it show 0 then.

Done during Turbo Testing and Tooling.

resources/qml/MachineSettings/ComboBoxWithOptions.qml

@@ -36,7 +36,7 @@ UM.TooltipArea
     property alias labelWidth: fieldLabel.width
     property alias optionModel: comboBox.model
 
-    property string tooltipText: propertyProvider.properties.description
+    property string tooltipText: propertyProvider.properties.description ? propertyProvider.properties.description : ""
 
     // callback functions
     property var forceUpdateOnChangeFunction: dummy_func

resources/qml/MachineSettings/GcodeTextArea.qml

@@ -1,4 +1,4 @@
-// Copyright (c) 2019 Ultimaker B.V.
+// Copyright (c) 2020 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.10
@@ -24,7 +24,7 @@ UM.TooltipArea
     property alias settingKey: propertyProvider.key
     property alias settingStoreIndex: propertyProvider.storeIndex
 
-    property string tooltip: propertyProvider.properties.description
+    property string tooltip: propertyProvider.properties.description ? propertyProvider.properties.description : ""
 
     property alias labelText: titleLabel.text
     property alias labelFont: titleLabel.font

resources/qml/MachineSettings/NumericTextFieldWithUnit.qml

@@ -1,4 +1,4 @@
-// Copyright (c) 2019 Ultimaker B.V.
+// Copyright (c) 2020 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.10
@@ -39,7 +39,7 @@ UM.TooltipArea
     property alias valueText: textFieldWithUnit.text
     property alias editingFinishedFunction: textFieldWithUnit.editingFinishedFunction
 
-    property string tooltipText: propertyProvider.properties.description
+    property string tooltipText: propertyProvider.properties.description ? propertyProvider.properties.description : ""
 
     property real minimum: 0
     property real maximum: Number.POSITIVE_INFINITY

resources/qml/MachineSettings/PrintHeadMinMaxTextField.qml

@@ -1,4 +1,4 @@
-// Copyright (c) 2019 Ultimaker B.V.
+// Copyright (c) 2020 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.10
@@ -35,15 +35,18 @@ NumericTextFieldWithUnit
     property string axisMinOrMax: "min"
     property var axisValue:
     {
-        var polygon = JSON.parse(propertyProvider.properties.value)
-        var item = (axisName == "x") ? 0 : 1
-        var result = polygon[0][item]
-        var func = (axisMinOrMax == "min") ? Math.min : Math.max
+        if(propertyProvider.properties.value === undefined) { //PropertyProvider not initialised yet or there is no global stack.
+            return 0;
+        }
+        var polygon = JSON.parse(propertyProvider.properties.value);
+        var item = (axisName == "x") ? 0 : 1;
+        var result = polygon[0][item];
+        var func = (axisMinOrMax == "min") ? Math.min : Math.max;
         for (var i = 1; i < polygon.length; i++)
         {
-            result = func(result, polygon[i][item])
+            result = func(result, polygon[i][item]);
         }
-        return result
+        return result;
     }
 
     valueText: axisValue

resources/qml/MachineSettings/SimpleCheckBox.qml

@@ -1,4 +1,4 @@
-// Copyright (c) 2019 Ultimaker B.V.
+// Copyright (c) 2020 Ultimaker B.V.
 // Cura is released under the terms of the LGPLv3 or higher.
 
 import QtQuick 2.10
@@ -32,7 +32,7 @@ UM.TooltipArea
     property alias labelFont: fieldLabel.font
     property alias labelWidth: fieldLabel.width
 
-    property string tooltip: propertyProvider.properties.description
+    property string tooltip: propertyProvider.properties.description ? propertyProvider.properties.description : ""
 
     // callback functions
     property var forceUpdateOnChangeFunction: dummy_func