[FIX] playground: properly resize editors when resizing panels

extras/playground/app.js

@@ -314,6 +314,7 @@ class TabbedEditor extends owl.Component {
     const session = this.sessions[this.state.currentTab];
     session.setValue(this.props[this.state.currentTab], -1);
     this.editor.setSession(session);
+    this.editor.resize();
   }
 
   willUnmount() {