title: Airflow will keep showing example dags even after removing it from configuration
body: <p>Airflow example dags remain in the UI even after I have turned off <code>load_examples = False</code> in config file.</p>
  
  <p><a href="https://i.stack.imgur.com/G8Qln.png" rel="noreferrer"><img src="https://i.stack.imgur.com/G8Qln.png" alt="enter image description here"></a></p>
  
  <p>The system informs the dags are not present in the dag folder but they remain in UI because the scheduler has marked it as active in the metadata database. </p>
  
  <p>I know one way to remove them from there would be to directly delete these rows in the database but off course this is not ideal.How should I proceed to remove these dags from UI? </p>