Add new method getExtraIntentAction() in DashboardFeatureProvider.

Add a new method to get the extra intent-filter action to be used
to query the dynamic dashboard tiles.

Bug: 32739952
Test: make RunSettingsRoboTests
Change-Id: I96d9d8bd32ebe34b7c0df00c3fb4d8900b476c94

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

@@ -242,4 +242,9 @@ public class DashboardFeatureProviderImplTest {
                 CategoryKey.CATEGORY_HOMEPAGE).isEmpty())
                 .isFalse();
     }
+
+    @Test
+    public void testGetExtraIntentAction_shouldReturnNull() {
+        assertThat(mImpl.getExtraIntentAction()).isNull();
+    }
 }