[transfer-engine] Avoid excessive notification action updates. JB#51671

When there are rapid consecutive action name changes (due to the auto-
generated action name being different each time a progress notification
is created), this confuses the UI as it needs to rebuild the action
data, and by the time the user triggers an action, it may already have
changed the UI to refer to a different action underneath. To avoid
this, just use the same action name each time.

src/transferengine.cpp

@@ -434,7 +434,11 @@ void TransferEnginePrivate::sendNotification(TransferEngineData::TransferType ty
                 useProgress = true;
 
             if (canCancel) {
-                remoteActions.append(Notification::remoteAction(QString(),
+                // Use a constant action name instead of an auto-generated one which is different
+                // every time, to avoid excessive changes to the action data which disrupts the UI.
+                static const QString cancelActionName = QStringLiteral("transferengine_cancel_transfer");
+
+                remoteActions.append(Notification::remoteAction(cancelActionName,
                                                                 //: Cancel the file transfer
                                                                 //% "Cancel"
                                                                 qtTrId("transferengine-no-cancel"),