fix(dialog): use dynamic height for dialog description

tests/ui/components/dialog/DialogDescription.qml

@@ -9,7 +9,9 @@ import 'qrc:/ui/style/components'
 Item {
     property alias text: description.text
 
-    height: text ? DialogStyle.description.height : DialogStyle.description.minHeight
+    height: (!text && DialogStyle.description.verticalMargin) || undefined
+    implicitHeight: (text && (description.implicitHeight + DialogStyle.description.verticalMargin)) ||
+        0
 
     Text {
         id: description

tests/ui/style/components/DialogStyle.qml

@@ -18,7 +18,6 @@ QtObject {
 
     property QtObject description: QtObject {
         property int fontSize: 12
-        property int height: 90    // Height with text.
-        property int minHeight: 25 // Height without text.
+        property int verticalMargin: 25
     }
 }