officejs_support_request_ui: use accessors on ERP5 documents

https://www.erp5.com/documentation/developer/guideline/coding/erp5-Guideline.Coding.Best.Practice#use-methods-to-access-properties-in-erp5

bt5/erp5_officejs_support_request_ui/SkinTemplateItem/portal_skins/erp5_officejs_support_request/SupportRequest_getSupportRequestStatisticsAsJson.py

@@ -19,8 +19,9 @@ count_by_state = {}
 count_by_date = {"le2": {}, "2to7": {}, "7to30": {}, "gt30": {}}
 
 for sr in support_request_list:
-  sr_date = sr.start_date
-  sr_state = sr.getProperty("simulation_state")
+  sr = sr.getObject()
+  sr_date = sr.getStartDate()
+  sr_state = sr.getSimulationState()
 
   if sr_state not in count_by_state:
     count_by_state[sr_state] = 0