luci-mod-network: fix creating joining wireless networks

Fixes: #5651
Fixes: 1c798d1a08 ("luci-base: form.js: allow nesting Grid and Table sections")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

modules/luci-mod-network/htdocs/luci-static/resources/view/network/wireless.js

@@ -1965,6 +1965,8 @@ return view.extend({
 					});
 				});
 			}).then(L.bind(function() {
+				ui.showModal(null, E('p', { 'class': 'spinning' }, [ _('Loading data…') ]));
+
 				return this.renderMoreOptionsModal(section_id);
 			}, this));
 		};