DialogHost accessibility issue

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### Bug explanation

The DialogHost seems to lost the focus when the window is minimized. When you restore it after, the focus goes to the main view even if the dialog host is always opened.

Steps to reproduce :
1. Open a DialogHost which contains some controls
2. Use the tab button to navigate on the DialogHost controls => The focus is on the DialogHost and its controls.
3. Minimize the app with the DialogHost opened
4. Maximize the app -> The DialogHost is always opened
5. Use the tab button again to get the focus => The DialogHost has not the focus, it is on the main View.
6. Close the DialogHost and reopened it
7. Use the tab button => The focus is on the DialogHost again

### Version

4.9.0

Comienza reproduciendo la secuencia de minimizar y restaurar con un DialogHost abierto y, después, sigue el punto de entrada de la gestión del foco de DialogHost. Verifica que restaurar la ventana conserve el foco dentro del DialogHost abierto y que cerrarlo y volver a abrirlo siga restaurando el foco como se describe.

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