QtWayland requests window activation on every focus object change

Whenever the focus object changes, for example as the result of the wayland compositor activating the window, QtWayland QPA requests window activation. It results in unnecessary traffic between the client and the compositor. It also conflicts with the compositor's policies, which in some cases, can "break" compositor features, e.g. https://bugs.kde.org/show_bug.cgi?id=466171

Ideally, xdg-activation should be used in response to concrete user actions, e.g. clicking a link in a web browser to open a new application, etc.