Center align suggestion tile action button.

Bug: 70573674
Test: visual
Change-Id: I9be36cb0f1c35c2062f01d03e01e0a74cb39f3a0
diff --git a/res/layout/suggestion_tile_with_button_v2.xml b/res/layout/suggestion_tile_with_button_v2.xml
index bedc6da..7042341 100644
--- a/res/layout/suggestion_tile_with_button_v2.xml
+++ b/res/layout/suggestion_tile_with_button_v2.xml
@@ -80,6 +80,7 @@
         <Button
             android:id="@android:id/primary"
             style="@style/ActionPrimaryButton"
+            android:layout_gravity="center"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="12dp"