erp5_maileva_connector: Use proxy role to not over design security

 This is required for ensure the transition to acknowledge occur, without require to over
 design security on maileva exchange and system even module.

bt5/erp5_maileva_connector/SkinTemplateItem/portal_skins/erp5_maileva_connector/MailevaExchange_processResponse.py

+from zExceptions import Unauthorized
+if REQUEST is not None:
+    raise Unauthorized
+
 connector = context.getResourceValue()
 connector.processResponse(response, context.getObject(), failed)

bt5/erp5_maileva_connector/SkinTemplateItem/portal_skins/erp5_maileva_connector/MailevaExchange_processResponse.xml

@@ -50,7 +50,15 @@
         </item>
         <item>
             <key> <string>_params</string> </key>
-            <value> <string>response, failed=False</string> </value>
+            <value> <string>response, failed=False, REQUEST=None</string> </value>
+        </item>
+        <item>
+            <key> <string>_proxy_roles</string> </key>
+            <value>
+              <tuple>
+                <string>Manager</string>
+              </tuple>
+            </value>
         </item>
         <item>
             <key> <string>id</string> </key>