[SB] Remove Disambiguation from StatusBarRoot.

We haven't used the diambiguation in awhile and it lets us reduce the
nesting inside the status bar composable.

Bug: 364360986
Flag: com.android.systemui.status_bar_root_modernization
Test: Status bar still looks good in portrait & landscape
Change-Id: If9c9f8d2638d98180378c736af8c3ff1bd911ddc