If source plugin extends another, create jobs through original plugin

MR: https://git.drupalcode.org/project/tmgmt/-/merge_requests/73

If you want to customize a plugin, don't define your own, alter the class instead.

I don't see how this makes sense, after this, your plugin wont' be involved anymore.

Without getting into whether the approach makes sense (in our case we wanted a separate UI from the original), we found an easier way to accomplish this without the patch:

  public function overviewFormSubmit(array $form, FormStateInterface $form_state, $type) {
    $current_plugin_id = $this->pluginId;
    $this->pluginId = 'content';

    parent::overviewFormSubmit($form, $form_state, $type);

    $this->pluginId = $current_plugin_id;
  }