Fix persistence of selected row when using the 'clear' button

Steps to reproduce:

• select a criterion, but do not add it to the query
• click on 'clear'
  => the selected row still appears (kept in the component submitted value) but as it's not really set, the operator and subwidgets are not displayed.

=> the component submitted value should be blanked, but that's not easy task as its id is not available from the 'clear' button