Adjust grid options margin and size

Screenshot: https://screenshot.googleplex.com/AWsM6nXFnMTgmaN.png

Bug: 185562658
Test: manual, at small, normal, and large display sizes
Change-Id: I8ef1c198b89f5e78d161df13d3e6e4009e666d12
diff --git a/res/layout/fragment_grid_picker.xml b/res/layout/fragment_grid_picker.xml
index 57aee6c..f700310 100644
--- a/res/layout/fragment_grid_picker.xml
+++ b/res/layout/fragment_grid_picker.xml
@@ -52,6 +52,7 @@
                 android:layout_width="match_parent"
                 android:layout_height="@dimen/options_container_height"
                 android:layout_marginBottom="@dimen/options_container_bottom_margin"
+                android:layout_marginHorizontal="@dimen/options_container_horizontal_margin"
                 app:layout_constraintBottom_toBottomOf="parent"
                 app:layout_constraintEnd_toEndOf="parent"
                 app:layout_constraintStart_toStartOf="parent" />
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 37718ec..ef9f417 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -32,7 +32,8 @@
     <dimen name="options_container_height">124dp</dimen>
     <dimen name="options_container_width">0dp</dimen>
     <dimen name="options_container_bottom_margin">12dp</dimen>
-    <dimen name="option_tile_width">88dp</dimen>
+    <dimen name="options_container_horizontal_margin">24dp</dimen>
+    <dimen name="option_tile_width">82dp</dimen>
     <dimen name="option_icon_size">16dp</dimen>
     <dimen name="theme_option_icon_sample_height">22dp</dimen>
     <dimen name="theme_option_icon_sample_width">22dp</dimen>