Fix link action resolution of current document in listings

The "drive edit" action link uses a "bare_link" widget type that resolves document in the iteration thanks to variable actionContextDocument.

This variable resolves to null when referenced in an action of type "link", because the current context variables are lost.

Steps to reproduce: contribute the following action to a standard Nuxeo:

<action id="listingTest" link="#{selectionActions.setSelectedValue(actionContextDocument.id)}"
  order="200" label="test" type="link" icon="/icons/delete_red.png">
  <category>BLOB_ACTIONS_LISTING</category>
</action>

When listing documents, the icon will appear in the listing. Clicking on it, the value passed as a parameter to the selectionActions#selectedValue method is always empty (instead of referencing the listing document id).

Note a similar fix was previously done on MetaValueExpression for NXP-17218.