[FIX] mass_mailing_event: stat button overlap

In some languages (e.g. German), the text on the stat button overlaps
the button next to it.

opw-1858981

addons/mass_mailing_event/i18n/mass_mailing_event.pot

@@ -15,13 +15,13 @@ msgstr ""
 "Content-Transfer-Encoding: \n"
 "Plural-Forms: \n"
 
+#. module: mass_mailing_event
+#: model:ir.ui.view,arch_db:mass_mailing_event.event_event_view_form_inherit_mass_mailing
+msgid "<span class=\"o_stat_text\">Mail Attendees</span>"
+msgstr ""
+
 #. module: mass_mailing_event
 #: model:ir.model,name:mass_mailing_event.model_event_event
 msgid "Event"
 msgstr ""
 
-#. module: mass_mailing_event
-#: model:ir.ui.view,arch_db:mass_mailing_event.event_event_view_form_inherit_mass_mailing
-msgid "Mail Attendees"
-msgstr ""
-

addons/mass_mailing_event/views/event_views.xml

@@ -10,7 +10,9 @@
                         name="action_mass_mailing_attendees"
                         icon="fa-envelope-o"
                         attrs="{'invisible': [('seats_expected', '=', 0)]}">
-                    Mail Attendees
+                    <div class="o_field_widget o_stat_info">
+                        <span class="o_stat_text">Mail Attendees</span>
+                    </div>
                 </button>
             </button>
         </field>