[shade] use the same configuration for NewStatusBarIcons in the shade

the bug: the shade uses the same underlying ModernStatusBarMobileView
that the status bar does. But it constructs it from a differnet context
(ModernShadeCarrierGroupMobileView). thus it was missing flag-specific
configuration

the fix: use the same configuration in the shade

Test: manual via demo mode. requires scene_container to make demo mode
work in this instance. Set 2 sims and fully expand the shade
Bug: 415670005
Flag: com.android.settingslib.flags.new_status_bar_icons
Flag: com.android.systemui.status_bar_root_modernization

Change-Id: I0669b449e58eb245a443ff63b3da1eea1d5fde5a