Use medium text size for the Discover label.

Change-Id: I5a04dd3304ea8dbc4e51f4910012d96b1104b3fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343638Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Peter Williamson <petewil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796669}

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

@@ -24,7 +24,7 @@
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_weight="1"
-        android:textAppearance="@style/TextAppearance.TextSmall.Secondary"
+        android:textAppearance="@style/TextAppearance.TextAccentMediumThick.Secondary"
         android:textDirection="locale" />
 
     <org.chromium.components.browser_ui.widget.listmenu.ListMenuButton