fix "Resolve conflicts" dialog not showing up

fix "Resolve conflicts" dialog not showing up

commit 00b616ba9d92a492b0c4e5101b58fff6506591ef removed the call to
`QScopedPointer::take` as it's considered deprecated in Qt 6.1 and
advises to use `std::unique_ptr` with `release()` instead

--> replace `QScopedPointer` with `std::unique_ptr` and call its
`release()` method as part of the cast to `QQuickWindow*`

Signed-off-by: Jyrki Gadinger <nilsding@nilsding.org>