Fixed restoring app position for multiscreen

[Reksotiv]

For multiple screens we need to use QWidget::restoreGeometry()
Source code: https://codebrowser.dev/qt5/qtbase/src/widgets/kernel/qwidget.cpp.html#7215
and QWidget::setGeometry() for comparison https://codebrowser.dev/qt5/qtbase/src/widgets/kernel/qwidget.cpp.html#7005

[scamille]

When a user closes the UI on a second monitor, this will still lead to the UI being opened again on the second monitor, correct?

And that is exactly an issue that leads to unrecoverable crashes for users in #5047 if they can't force the UI to open on their primary monitor.

Besides that, sure using restoreGeometry instead of setGeometry is better, thanks for the input.

[Reksotiv]

Works fine on two monitors, unlike setGeometry. It would be nice to test on more monitors