Issue 7214 - Hide Learn more from private tabs

mobile/android/app/src/photon/res/layout/private_tabs_panel.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- This Source Code Form is subject to the terms of the Mozilla Public
    - License, v. 2.0. If a copy of the MPL was not distributed with this
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 
 <merge xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:gecko="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        tools:layout_height="match_parent"
        tools:layout_width="match_parent"
@@ skipping 36 matching lines @@
                 style="@style/TextAppearance.PrivateTab.Description"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="center_horizontal"
                 android:layout_marginBottom="36dp"
                 android:gravity="center_horizontal"
                 android:lineSpacingMultiplier="1.3"
                 android:text="@string/private_tab_panel_description2"
                 android:textColor="@color/photon_text_secondary"/>
 
+            <!-- We always hide the learn more link
+            See https://issues.adblockplus.org/ticket/7214 -->
             <TextView
                 style="@style/TextAppearance.PrivateTab.Description"
                 android:id="@+id/learn_more_link"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="center_horizontal"
                 android:clickable="true"
                 android:text="@string/private_tab_learn_more"
+                android:visibility="gone"
                 android:textColor="@color/link_blue"/>
 
         </LinearLayout>
 
     </ScrollView>
 
     <!-- Note: for an unknown reason, scrolling in the TabsLayout
          does not work unless it is laid out after the empty view. -->
     <view
         android:id="@+id/private_tabs_layout"
         style="@style/TabsLayout"
         class="org.mozilla.gecko.tabs.TabsPanel$TabsLayout"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:visibility="gone"
         gecko:tabs="tabs_private"/>
 
 </merge>