Chatbox id for all property refs

Change the chatbox id to root and use for all references to it properties. Using root.currentRoom is needed for the chatbar to be visible in KF6

src/qml/Component/ChatBox/ChatBox.qml

@@ -30,7 +30,7 @@ import org.kde.neochat 1.0
  * @sa ChatBar
  */
 ColumnLayout {
-    id: chatBox
+    id: root
 
     /**
      * @brief The current room that user is viewing.
@@ -63,7 +63,7 @@ ColumnLayout {
     ChatBar {
         id: chatBar
 
-        visible: currentRoom.canSendEvent("m.room.message")
+        visible: root.currentRoom.canSendEvent("m.room.message")
 
         Layout.fillWidth: true
         Layout.minimumHeight: Math.max(Kirigami.Units.gridUnit * 2, implicitHeight + Kirigami.Units.largeSpacing)
@@ -78,7 +78,7 @@ ColumnLayout {
         }
 
         onMessageSent: {
-            chatBox.messageSent();
+            root.messageSent();
         }
     }