erp5_certificate_authority: Fix up script and set portal skins priority order

Prefer to use Login_checkExistence from this Skins over the version on erp5_base.

bt5/erp5_certificate_authority/SkinTemplateItem/portal_skins/erp5_certificate_authority.xml

@@ -9,7 +9,18 @@
         <item>
             <key> <string>_local_properties</string> </key>
             <value>
-              <tuple/>
+              <tuple>
+                <dictionary>
+                  <item>
+                      <key> <string>id</string> </key>
+                      <value> <string>business_template_skin_layer_priority</string> </value>
+                  </item>
+                  <item>
+                      <key> <string>type</string> </key>
+                      <value> <string>float</string> </value>
+                  </item>
+                </dictionary>
+              </tuple>
             </value>
         </item>
         <item>
@@ -18,6 +29,10 @@
               <tuple/>
             </value>
         </item>
+        <item>
+            <key> <string>business_template_skin_layer_priority</string> </key>
+            <value> <float>1.0</float> </value>
+        </item>
         <item>
             <key> <string>id</string> </key>
             <value> <string>erp5_certificate_authority</string> </value>

bt5/erp5_certificate_authority/SkinTemplateItem/portal_skins/erp5_certificate_authority/Login_checkExistence.py

@@ -6,7 +6,7 @@ if portal_type in ("ERP5 Login", "Certificate Login"):
   portal_type = ("ERP5 Login", "Certificate Login")
 
 return context.getPortalObject().Base_checkLoginExistence(
-  portal_type=context.getPortalType(),
+  portal_type=portal_type,
   reference=context.getReference(),
   ignore_uid=context.getUid(),
   ignore_user_uid=context.getParentValue().getUid(),