Fix wrong demention value for fre_button_bar_height

The previous dimension assuming the button height is 42dp, while minimum
touch target size is now 48dp.

Bug: 1127528
Change-Id: Ia9946360d1dc7ae261494f460cf8cb860766e526
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560605
Commit-Queue: Wenyu Fu <wenyufu@chromium.org>
Auto-Submit: Wenyu Fu <wenyufu@chromium.org>
Reviewed-by: Sky Malice <skym@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831968}

chrome/android/java/res/layout/fre_data_reduction_proxy_lite_mode.xml

@@ -79,7 +79,6 @@
         </LinearLayout>
     </ScrollView>
 
-    <!-- fre_button_bar_height = 52dp = layout_height + layout_marginBottom -->
     <org.chromium.ui.widget.ButtonCompat
         android:id="@+id/next_button"
         android:layout_width="wrap_content"

chrome/android/java/res/values/dimens.xml

@@ -161,7 +161,8 @@
     <dimen name="fre_policy_privacy_disclaimer_icon_padding">8dp</dimen>
 
     <dimen name="fre_button_vertical_margin">24dp</dimen>
-    <dimen name="fre_button_bar_height">62dp</dimen>
+    <!-- fre_button_bar_height = 68dp = layout_height (48dp) + 2 * layout_marginBottom(10dp) -->
+    <dimen name="fre_button_bar_height">68dp</dimen>
     <!-- fre_button_bar_height = button_height(48dp) + fre_button_vertical_margin * 2-->
     <dimen name="fre_tos_button_bar_height">96dp</dimen>
     <!-- fre_bottom_loading_spinner_margin = (fre_tos_button_bar_height - fre_bottom_loading_spinner_size) / 2-->