Tablet Settings Layout is no longer stretched

Change-Id: If4a883077f41b859f4e8aaf92a4f397b94814137
Fixes: 31583422
Tests: Visual Inspection

res/layout/dashboard_container_header.xml

@@ -20,4 +20,6 @@
     android:id="@+id/sliding_tabs"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
+    android:layout_marginLeft="@dimen/dashboard_header_margin_left"
+    android:layout_marginRight="@dimen/dashboard_header_margin_right"
     android:background="?android:attr/colorPrimary"/>

res/layout/settings_main_dashboard.xml

@@ -21,4 +21,5 @@
              android:id="@+id/main_content"
              android:layout_height="match_parent"
              android:layout_width="match_parent"
+             android:background="@color/material_grey_300"
              />

res/layout/support_tile_spacer.xml

@@ -15,7 +15,7 @@
      limitations under the License.
 -->
 
-<Space
+<View
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="@dimen/support_spacer_height"