erp5_officejs_support_request_ui: Avoid to hardcode sort_on in the python script

Because this breaks the sort and filter buttons in the new ERP5 UI

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

-if 'sort_on' in kw:
-  del kw['sort_on']
-
-return context.searchFolder(sort_on=[
-    ('modification_date', 'descending'),
-    # XXX to get stable test result, we also sort by start date (because modification date
-    # has a one second precision)
-    ('delivery.start_date', 'descending'),
-    ], **kw)

bt5/erp5_officejs_support_request_ui/SkinTemplateItem/portal_skins/erp5_officejs_support_request/Folder_searchFolderSortByReferenceDescending.xml

-<?xml version="1.0"?>
-<ZopeData>
-  <record id="1" aka="AAAAAAAAAAE=">
-    <pickle>
-      <global name="PythonScript" module="Products.PythonScripts.PythonScript"/>
-    </pickle>
-    <pickle>
-      <dictionary>
-        <item>
-            <key> <string>Script_magic</string> </key>
-            <value> <int>3</int> </value>
-        </item>
-        <item>
-            <key> <string>_bind_names</string> </key>
-            <value>
-              <object>
-                <klass>
-                  <global name="NameAssignments" module="Shared.DC.Scripts.Bindings"/>
-                </klass>
-                <tuple/>
-                <state>
-                  <dictionary>
-                    <item>
-                        <key> <string>_asgns</string> </key>
-                        <value>
-                          <dictionary>
-                            <item>
-                                <key> <string>name_container</string> </key>
-                                <value> <string>container</string> </value>
-                            </item>
-                            <item>
-                                <key> <string>name_context</string> </key>
-                                <value> <string>context</string> </value>
-                            </item>
-                            <item>
-                                <key> <string>name_m_self</string> </key>
-                                <value> <string>script</string> </value>
-                            </item>
-                            <item>
-                                <key> <string>name_subpath</string> </key>
-                                <value> <string>traverse_subpath</string> </value>
-                            </item>
-                          </dictionary>
-                        </value>
-                    </item>
-                  </dictionary>
-                </state>
-              </object>
-            </value>
-        </item>
-        <item>
-            <key> <string>_params</string> </key>
-            <value> <string>**kw</string> </value>
-        </item>
-        <item>
-            <key> <string>id</string> </key>
-            <value> <string>Folder_searchFolderSortByReferenceDescending</string> </value>
-        </item>
-      </dictionary>
-    </pickle>
-  </record>
-</ZopeData>

bt5/erp5_officejs_support_request_ui/SkinTemplateItem/portal_skins/erp5_officejs_support_request/SupportRequestModule_viewLastSupportRequestList/listbox.xml

@@ -345,7 +345,16 @@
                 <item>
                     <key> <string>sort</string> </key>
                     <value>
-                      <list/>
+                      <list>
+                        <tuple>
+                          <string>modification_date</string>
+                          <string>descending</string>
+                        </tuple>
+                        <tuple>
+                          <string>delivery.start_date</string>
+                          <string>descending</string>
+                        </tuple>
+                      </list>
                     </value>
                 </item>
                 <item>
@@ -376,7 +385,7 @@
       <dictionary>
         <item>
             <key> <string>method_name</string> </key>
-            <value> <string>Folder_searchFolderSortByReferenceDescending</string> </value>
+            <value> <string>searchFolder</string> </value>
         </item>
       </dictionary>
     </pickle>