ContentDialog and MessageBox IsFooterVisible

[IOL0ol1]

Is your feature request related to a problem? Please describe

1. ContentDialog.IsFooterVisible=false, but CornerRadius=8,8,0,0 looks no good.

2. Messagebox add IsFooterVisible.

Describe the solution you'd like

ContentDialog CornerRadius change with IsFooterVisible
Messagebox add IsFooterVisible like ContentDialog

Describe alternatives you've considered

No response

Additional context

[Pyth0ff]

This is a duplicate of #1309.