Fix widget 'routing_task_target_document'

Widget routing_task_target_document used in the content view under HOME > Workflows does not properly render the linked property (see screenshot-1.png).

How to reproduce:

1. install Nuxeo
2. install JSF UI
3. start a workflow
4. head over to HOME > Workflows

Expected result: the document ids should be resolved
Actual result: an error message Document not found or not visible. is shown

As the linked property is a multi-valued property, it should use a widget type multipleDocumentsSuggestion instead of singleDocumentSuggestion. This seems to be related to NXP-21025 and more specifically to this commit.

Here is a workaround, a Studio XML extension:

  <require>org.nuxeo.ecm.platform.routing.dashboard.layouts</require>

  <extension target="org.nuxeo.ecm.platform.forms.layout.WebLayoutManager"
    point="widgets">

    <widget name="routing_task_target_document" type="multipleDocumentsSuggestion">
      <labels>
        <label mode="any">label.document</label>
      </labels>
      <translated>true</translated>
      <fields>
        <field>data.nt.targetDocumentsIds</field>
      </fields>
    </widget>

  </extension>