erp5_officejs_support_request_ui: fix undefined error on gadget initialization

I tried to embeed the support request homepage in a "dashboard" page of renderjs website. Without this change I got Error: TypeError: Cannot read property 'field_listbox_begin_from' of undefined .

I think the purpose of the previous call to changeState is to initialize the gadget, unfortunately the result is dropped. I hope this change follows correctly the code.

If some mandatory parameters were to give to the gadget on initialization, maybe some information should be given about them