slapos_erp5: do not allow Sale function to modify Subscription Request

Let's automate everything for now

master/bt5/slapos_erp5/PortalTypeRolesTemplateItem/Subscription%20Request.xml

 <type_roles>
-  <role id='Assignee'>
+  <role id='Auditor'>
    <property id='title'>Sale Agent</property>
    <multi_property id='categories'>local_role_group/function</multi_property>
    <multi_property id='category'>function/sale/agent</multi_property>
    <multi_property id='base_category'>function</multi_property>
   </role>
-  <role id='Assignor'>
+  <role id='Auditor'>
    <property id='title'>Sale Manager</property>
    <multi_property id='categories'>local_role_group/function</multi_property>
    <multi_property id='category'>function/sale/manager</multi_property>