Fix crash when trying to edit your message on a wide screen

This only seems to happen when the window is maximized, specifically
the height of the window. This seems to be a weird TextArea issue (or
something else in our TimelineView) but until that's found out, a
Qt.callLater will prevent this annoying crash.

BUG: 503846

(cherry picked from commit 906fb97259)

src/timeline/ChatBarComponent.qml

@@ -37,7 +37,7 @@ QQC2.TextArea {
     Layout.maximumWidth: root.maxContentWidth
     Layout.minimumHeight: chatButtons.height + topPadding + bottomPadding
 
-    Component.onCompleted: _private.updateText()
+    Component.onCompleted: Qt.callLater(() => _private.updateText())
 
     topPadding: Kirigami.Units.smallSpacing
     bottomPadding: Kirigami.Units.smallSpacing