Fix for 2428 from a-c

In 2428 from android-components, they removed part of
the tab layout XML for localization/usability and fenix
copied that file directly. Fenix needs to make the
equivalent change. This patch does that.

app/src/main/res/layout/mozac_ui_tabcounter_layout.xml

@@ -19,7 +19,7 @@
             android:id="@+id/counter_box"
             android:layout_width="24dp"
             android:layout_height="24dp"
-            android:contentDescription="@string/mozac_ui_tabcounter_description"
+            android:importantForAccessibility="no"
             android:src="@drawable/mozac_ui_tabcounter_box"/>
 
         <!-- This text size auto adjusts based on num digits in `TabCounter` -->