lok: fix welded dialogs

lok: fix welded dialogs

In the tiled rendering case the dialogs, run asynchronous due
to multiple user access. In order to send the messages
to the client side, the dialog  has to hook
a LOKNotifier in the constructor of the SfxViewShell.

However, the new weld wrapper classes use the Frame Window,
(i.e. Window::GetFarmeWeld()), as a parent of the dialogs.

On the other hand, in order to avoid getting the interface
implementation inside implementation classes, it has been
created a new method Window::GetFrameWindow(), otherwise
I have to do a bureaucratic conversion between Interfaces
to Implementations ( i.e. UnoWrapperBase::GetUnoWrapper() )

Change-Id: I32c34d82a89211a025250e65a05ce47d30efa0b8
Reviewed-on: https://gerrit.libreoffice.org/84215
Tested-by: Jenkins
Reviewed-by: Henry Castro <hcastro@collabora.com>