erp5_payzen_secure_payment: service_api_key is mandatory (add constraint)

   Otherwise, alarms to fetch what was paid (status) don't work.

bt5/erp5_payzen_secure_payment/PropertySheetTemplateItem/portal_property_sheets/PayzenService/service_api_key_constraint.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="String Attribute Match Constraint" module="erp5.portal_type"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>_identity_criterion</string> </key>
+            <value>
+              <persistent> <string encoding="base64">AAAAAAAAAAI=</string> </persistent>
+            </value>
+        </item>
+        <item>
+            <key> <string>_local_properties</string> </key>
+            <value>
+              <tuple>
+                <dictionary>
+                  <item>
+                      <key> <string>id</string> </key>
+                      <value> <string>message_property_not_set</string> </value>
+                  </item>
+                  <item>
+                      <key> <string>type</string> </key>
+                      <value> <string>string</string> </value>
+                  </item>
+                </dictionary>
+              </tuple>
+            </value>
+        </item>
+        <item>
+            <key> <string>_range_criterion</string> </key>
+            <value>
+              <persistent> <string encoding="base64">AAAAAAAAAAM=</string> </persistent>
+            </value>
+        </item>
+        <item>
+            <key> <string>constraint_property</string> </key>
+            <value>
+              <tuple>
+                <string>service_api_key</string>
+              </tuple>
+            </value>
+        </item>
+        <item>
+            <key> <string>description</string> </key>
+            <value>
+              <none/>
+            </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>service_api_key_constraint</string> </value>
+        </item>
+        <item>
+            <key> <string>message_attribute_not_match</string> </key>
+            <value> <string>service_api_key  has to be set.</string> </value>
+        </item>
+        <item>
+            <key> <string>message_no_such_property</string> </key>
+            <value> <string>service_api_key has to be set.</string> </value>
+        </item>
+        <item>
+            <key> <string>message_property_not_set</string> </key>
+            <value> <string>Certificate has to be set.</string> </value>
+        </item>
+        <item>
+            <key> <string>portal_type</string> </key>
+            <value> <string>String Attribute Match Constraint</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+  <record id="2" aka="AAAAAAAAAAI=">
+    <pickle>
+      <global name="PersistentMapping" module="Persistence.mapping"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>data</string> </key>
+            <value>
+              <dictionary/>
+            </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+  <record id="3" aka="AAAAAAAAAAM=">
+    <pickle>
+      <global name="PersistentMapping" module="Persistence.mapping"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>data</string> </key>
+            <value>
+              <dictionary/>
+            </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>