Update height of SliceView

So it can display 6 items at most, not 4 items

Bug: 120803703
Test: Manual
Change-Id: Id34398903d0f81bebee3e02c024d21ad2e68578f

res/layout/slice_preference_layout.xml

@@ -25,5 +25,5 @@
     <androidx.slice.widget.SliceView
         android:id="@+id/slice_view"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"/>
+        android:layout_height="@dimen/slice_preference_group_height"/>
 </FrameLayout>

res/values/dimens.xml

@@ -370,4 +370,6 @@
     <dimen name="qrcode_size">264dp</dimen>
     <dimen name="qrcode_preview_size">360dp</dimen>
 
+    <!-- Height for slice preference, which contains 6 items at most -->
+    <dimen name="slice_preference_group_height">360dp</dimen>
 </resources>

src/com/android/settings/slices/SlicePreference.java

@@ -44,6 +44,7 @@ public class SlicePreference extends LayoutPreference {
     private void init() {
         mSliceView = findViewById(R.id.slice_view);
         mSliceView.showTitleItems(true);
+        mSliceView.setScrollable(false);
     }
 
     public void onSliceUpdated(Slice slice) {

src/com/android/settings/slices/SlicePreferenceController.java

@@ -50,7 +50,6 @@ public class SlicePreferenceController extends BasePreferenceController implemen
     @Override
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);
-
         mSlicePreference = screen.findPreference(getPreferenceKey());
     }