[FIX] im_livechat: prevent adding portal users are operator

task-3433465

closes odoo/odoo#129140

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/im_livechat/views/im_livechat_channel_views.xml

@@ -97,7 +97,7 @@
                         <notebook>
                             <page string="Operators" name="operators">
                                 <group>
-                                    <field name="user_ids" nolabel="1" colspan="2">
+                                    <field name="user_ids" nolabel="1" colspan="2" domain="[['groups_id', 'not in', %(base.group_portal)d]]">
                                         <kanban>
                                             <field name="id"/>
                                             <field name="name"/>