Add the share screen privacy indicator chip

This cl added the corresponding interactor, viewmodel etc for
this chip. The real pop up logic while clicking the chip will
be implemented in a follow up cl.

A config is added to determine whether we should show this
privacy indicator after triggering the share screen session.
It is set to false by default, and set to true on desktop
on ag/35615103.

Screenshot: b/437918351#comment2

Bug: 437918351
Flag: com.android.systemui.status_bar_popup_chips
Test: ShareScreenPrivacyIndicatorInteractorTest
      ShareScreenPrivacyIndicatorViewModelTest
Change-Id: Ib66780b43c1a443689a238be26fa21065c266b41