[accounting] Revert "required" attribute on "from_date" in Trial Balance report

bt5/erp5_accounting/SkinTemplateItem/portal_skins/erp5_accounting/AccountModule_viewTrialBalanceReportDialog/your_from_date.xml

@@ -9,9 +9,7 @@
         <item>
             <key> <string>delegated_list</string> </key>
             <value>
-              <list>
-                <string>required</string>
-              </list>
+              <list/>
             </value>
         </item>
         <item>
@@ -79,10 +77,6 @@
                     <key> <string>form_id</string> </key>
                     <value> <string>AccountModule_viewDialogFieldLibrary</string> </value>
                 </item>
-                <item>
-                    <key> <string>required</string> </key>
-                    <value> <int>1</int> </value>
-                </item>
                 <item>
                     <key> <string>target</string> </key>
                     <value> <string>Click to edit the target</string> </value>