Change color of busyIndicator according to the Theme

Also for the text "No printer found in your network" in AddNetworkPrinterScrollView

CURA-7627

resources/qml/WelcomePages/AddCloudPrintersView.qml

@@ -63,6 +63,7 @@ Item
                 id: waitingIndicator
                 anchors.horizontalCenter: parent.horizontalCenter
                 running: searchingForCloudPrinters
+                palette.dark: UM.Theme.getColor("text")
             }
             Label
             {

resources/qml/WelcomePages/AddNetworkPrinterScrollView.qml

@@ -41,6 +41,7 @@ Item
             anchors.left: parent.left
             anchors.leftMargin: UM.Theme.getSize("default_margin").width
             text: catalog.i18nc("@label", "There is no printer found over your network.")
+            color: UM.Theme.getColor("text")
             renderType: Text.NativeRendering
             verticalAlignment: Text.AlignVCenter
             visible: networkPrinterListView.count == 0  // Do not show if there are discovered devices.