Reuse the dimen of preview pager height percent

continue ag/11587711

If the value get changed, all tabs would still be consistent:
https://cs.corp.google.com/android/packages/apps/WallpaperPicker2/res/values/dimens.xml?q=preview_pager_maximum_height_ratio&g=0&l=199

Test: Manually
Bug: 157111978
Change-Id: I3440ccfc8f2db4c828dea60b5ac3f88aef4a2b13
diff --git a/res/layout/fragment_grid_picker.xml b/res/layout/fragment_grid_picker.xml
index ddb9917..7f35689 100644
--- a/res/layout/fragment_grid_picker.xml
+++ b/res/layout/fragment_grid_picker.xml
@@ -47,7 +47,7 @@
                 app:layout_constraintBottom_toTopOf="@id/options_title"
                 app:layout_constraintHeight_max="@dimen/preview_pager_max_height"
                 app:layout_constraintVertical_bias="0.0"
-                app:layout_constraintHeight_percent="0.7">
+                app:layout_constraintHeight_percent="@dimen/preview_pager_maximum_height_ratio">
                 <include layout="@layout/grid_preview_card"/>
             </FrameLayout>
 
diff --git a/res/layout/fragment_theme_picker.xml b/res/layout/fragment_theme_picker.xml
index 09f4819..c61c389 100644
--- a/res/layout/fragment_theme_picker.xml
+++ b/res/layout/fragment_theme_picker.xml
@@ -45,7 +45,7 @@
                 app:layout_constraintBottom_toTopOf="@id/options_container"
                 app:layout_constraintHeight_max="@dimen/preview_pager_max_height"
                 app:layout_constraintVertical_bias="0.0"
-                app:layout_constraintHeight_percent="0.7">
+                app:layout_constraintHeight_percent="@dimen/preview_pager_maximum_height_ratio">
                 <include layout="@layout/theme_preview_card_v2"/>
             </FrameLayout>