fix(ui/modules/Linphone/Chat/Chat): parent may be `null` in delegate

tests/src/app/App.hpp

@@ -18,6 +18,7 @@ class App : public QApplication {
 public:
   static void init (int &argc, char **argv) {
     if (!m_instance) {
+      // Instance must be exists before content.
       m_instance = new App(argc, argv);
       m_instance->initContentApp();
     }

tests/ui/modules/Linphone/Chat/Chat.qml

@@ -90,9 +90,9 @@ ColumnLayout {
       }
 
       anchors {
-        left: parent.left
+        left: parent ? parent.left : undefined
         leftMargin: ChatStyle.entry.leftMargin
-        right: parent.right
+        right: parent ? parent.right : undefined
 
         // Ugly. I admit it, but it exists a problem, without these
         // lines the extra content message is truncated.
@@ -106,7 +106,6 @@ ColumnLayout {
           ChatStyle.entry.message.outgoing.sendIconSize
       }
       implicitHeight: layout.height + ChatStyle.entry.bottomMargin
-      width: parent.width
 
       // -------------------------------------------------------------