Implement the collapsible feature of conditional card

Add two control views for conditional card to achieve collapsibility.
One of these control views is a footer that is appended to the last
position when expanding all conditional cards. The other is a header
that is used in the collapsed state of conditional cards.

Bug: 119593268
Bug: 113451905
Test: visual, robotests
Change-Id: I39e79b8925a9e3e4ce80c422bcd0ba889aba5f6a

src/com/android/settings/homepage/contextualcards/ContextualCardsAdapter.java

@@ -129,5 +129,7 @@ public class ContextualCardsAdapter extends RecyclerView.Adapter<RecyclerView.Vi
             // Adding items to empty list, should animate.
             mRecyclerView.scheduleLayoutAnimation();
         }
+
+        //TODO(b/119465242): flickering conditional cards after collapsing/expanding
     }
 }