[FIX] mass_mailing_sms : diplay count pf contact list incorrect

In the sms marketing, the display name of the contact list was wrong
during the search of the many2one widget (contact list field,
count of valid number was the count of valid email).
Add a context attribute on the widget depending of the global context
to force the rigth count.

TASK_ID : 2078918

addons/mass_mailing_sms/views/mailing_mailing_views.xml

@@ -112,6 +112,12 @@
             <xpath expr="//field[@name='user_id']" position="after">
                 <field name="sms_allow_unsubscribe" attrs="{'invisible': [('mailing_type', '!=', 'sms')]}"/>
             </xpath>
+
+            <xpath expr="//field[@name='contact_list_ids']" position="attributes">
+                <attribute name="context">
+                    {'mailing_sms' : context.get('mailing_sms')}
+                </attribute>
+            </xpath>
             <!-- Option page tweaks -->
             <xpath expr="//field[@name='email_from']" position="attributes">
                 <attribute name="attrs">{