erp5_workflow: change the transition's property expression's type to string.

bt5/erp5_workflow/PropertySheetTemplateItem/portal_property_sheets/Transition/expression_property.xml

@@ -10,7 +10,7 @@
             <key> <string>categories</string> </key>
             <value>
               <tuple>
-                <string>elementary_type/tales</string>
+                <string>elementary_type/string</string>
               </tuple>
             </value>
         </item>