title: ngx-formly: How to trigger blur event in formly for a custom control like dateTimePicker?
body: <p>Blur event is not triggering for custom control in angular formly. How to bind blur event for a custom component ? I have created custom control for dateTimePicker and  using Material UI with angular version 9, formly version 5.5</p>
  <pre><code>export class AppComponent {
    form = new FormGroup({});
    model: any = {};
    options: FormlyFormOptions = {};
    fields: FormlyFieldConfig[] = [
      {
        key: &quot;DateTimePicker&quot;,
        type: &quot;dateTime&quot;,
        templateOptions: {
          label: &quot;Accept terms&quot;,
          description: &quot;In order to proceed, please accept terms&quot;,
          pattern: &quot;true&quot;,
          required: true,
          blur: () =&gt; {
            console.log(&quot;blur called&quot;);
          }
        },
        validation: {
          messages: {
            pattern: &quot;Please accept the terms&quot;
          }
        }
      }
    ];
  }
  </code></pre>