Use the ChatBar Component for new thread messages

![image](/uploads/a24dea919e7f165d602991659f517c22/image.png){width=148 height=210}

Note: there is still an issue where after starting a new thread the threaded messages only appear after a restart as the root event needs re-downloading from the server to get the thread info added. My plan is to tackle this next.

src/timeline/ChatBarComponent.qml

@@ -118,7 +118,7 @@ QQC2.TextArea {
                 text: i18nc("@action:button", "Cancel")
                 icon.name: "dialog-close"
                 onTriggered: {
-                    root.chatBarCache.editId = "";
+                    root.chatBarCache.clearRelations();
                 }
                 shortcut: "Escape"
             }