[DesktopStatusBar] Do not show ShadeHeader

The desktop status bar needs to stay visible
when the shade is visible. Due to this we do
not need to show the ShadeHeader.

Test: manual
Bug: 433589833
Flag: com.android.systemui.status_bar_for_desktop
Change-Id: Ic7f41df13b00c6d0bf09c51d2031b9bdf705f9c8