Merge PR #1468 into 17.0

Signed-off-by hbrunn

mail_activity_board/static/src/components/chatter/chatter.xml

@@ -6,6 +6,7 @@
         t-inherit-mode="extension"
     >
          <xpath expr="//button[hasclass('o-mail-Chatter-activity')]" position="after">
+            <t t-if="props.hasActivities">
                 <button
                     class="btn btn-link o_ChatterTopbar_button"
                     type="button"
@@ -14,6 +15,7 @@
                 >
                     <i class="fa fa-list" /> View Activities
                 </button>
+            </t>
         </xpath>
     </t>
 </templates>