Fix minimize and close bugs

refs #8225

To ensure the GUI closes when the "Minimize on close" window option is disabled, and the "Minimize to the tray instead of the taskbar" window option is enbaled, remove a check made against the "Minimize to the tray instead of the taskbar" value, made during GUI closure.

To ensure the GUI minimizes to the taskbar when the "Minimize on close" window option is enabled, and the "Minimize to the tray instead of the taskbar" window option is disabled, minimize the GUI and ignore the closure event.