fix: propsTypes warning

* the recordRestrictionGracePeriod is not an object. here
  https://github.com/inveniosoftware/invenio-app-rdm/blob/master/invenio_app_rdm/records_ui/templates/semantic-ui/invenio_app_rdm/records/deposit.html#L45
  it is converted to number only

invenio_app_rdm/theme/assets/semantic-ui/js/invenio_app_rdm/deposit/RDMDepositForm.js

@@ -699,7 +699,7 @@ export class RDMDepositForm extends Component {
 RDMDepositForm.propTypes = {
   groupsEnabled: PropTypes.bool.isRequired,
   config: PropTypes.object.isRequired,
-  recordRestrictionGracePeriod: PropTypes.object.isRequired,
+  recordRestrictionGracePeriod: PropTypes.number.isRequired,
   allowRecordRestriction: PropTypes.bool.isRequired,
   record: PropTypes.object.isRequired,
   preselectedCommunity: PropTypes.object,