Limit the suggestions to be shown to 5.

- when creating the dashboard data, pass the sublist of suggestions to
cap the total number of suggestions to be shown to 5.
- if user swipe away the suggestion, it will only remove the suggestion
from the suggestion adapater, and will not trigger rebuilding the whole
UI.

Bug: 64072051
Change-Id: I1efabeb2a805c670007c631d3ccb0fdfbde7b55a
Fix: 63309218
Test: make RunSettingsRoboTests

tests/robotests/src/com/android/settings/dashboard/DashboardSummaryTest.java

@@ -118,9 +118,8 @@ public class DashboardSummaryTest {
     }
 
     @Test
-    public void onSuggestionDismissed_categoryShouldBeRefreshed() {
-        doNothing().when(mSummary).rebuildUI();
+    public void onSuggestionDismissed_shouldNotRebuildUI() {
         mSummary.onSuggestionDismissed(mock(Tile.class));
-        verify(mSummary).rebuildUI();
+        verify(mSummary, never()).rebuildUI();
     }
 }