Fix message long press

Add a tap handler so that long press events in the text of a message can be captured. This should make mobile menus work on text messages again.

src/qml/Component/Timeline/MessageDelegate.qml

@@ -50,6 +50,12 @@ TimelineContainer {
             isReply: root.isReply
 
             textMessage: root.display
+
+            TapHandler {
+                enabled: !label.hoveredLink
+                acceptedButtons: Qt.LeftButton
+                onLongPressed: root.openContextMenu()
+            }
         }
         Loader {
             Layout.fillWidth: true