TheHiveButton: don't open empty observable lists

thehive_button/public/vis_controller.js

@@ -512,7 +512,7 @@ class ObservablesTable extends Component {
         <EuiAccordion
           id="accordion-{this.props.fieldName}"
           buttonContent={<EuiTitle size="xs"><h4>{this.props.fieldName.replace(/\.keyword$/, "")} ({this.props.obsSel.length}/{n_obs})</h4></EuiTitle>}
-          initialIsOpen={n_obs <= 3}
+          initialIsOpen={n_obs > 0 && n_obs <= 3}
         >
           <EuiBasicTable
             ref={this.tableRef}