Removes summary text from Instant Apps details

Test: Robolectric test to ensure header item is GONE.

Bug: 36512295
Change-Id: I020e90d6521c853e67ae600e5786445a8469a934
(cherry picked from commit 14a258443f)

tests/robotests/src/com/android/settings/applications/AppHeaderControllerTest.java

@@ -287,6 +287,8 @@ public class AppHeaderControllerTest {
         assertThat(label.getVisibility()).isEqualTo(View.VISIBLE);
         assertThat(label.getText()).isEqualTo(
                 appHeader.getResources().getString(R.string.install_type_instant));
+        assertThat(appHeader.findViewById(R.id.app_detail_summary).getVisibility())
+                .isEqualTo(View.GONE);
     }
 
     @Test