slapos_cloud: Do not hardcode payzen test configuration on preference

  This should be set from the test or by the user while configure payzen.

master/bt5/slapos_cloud/PreferenceTemplateItem/portal_preferences/slapos_default_system_preference.xml

@@ -253,14 +253,6 @@
             <key> <string>preferred_password_lifetime_expire_warning_duration</string> </key>
             <value> <int>336</int> </value>
         </item>
-        <item>
-            <key> <string>preferred_payzen_integration_site</string> </key>
-            <value> <string>portal_integrations/slapos_payzen_test_integration</string> </value>
-        </item>
-        <item>
-            <key> <string>preferred_payzen_payment_service_reference</string> </key>
-            <value> <string>PSERV-Payzen-Test</string> </value>
-        </item>
         <item>
             <key> <string>preferred_registration_resource</string> </key>
             <value> <string>service_module/vifib_registration</string> </value>