Fix 'userprofile' content enricher

<?xml version="1.0"?>
<xs:schema targetNamespace="http://www.nuxeo.core/ecm/schemas/userprofile/"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:nxs="http://www.nuxeo.core/ecm/schemas/userprofile/">

  <xs:include schemaLocation="core-types.xsd" />

  <xs:element name="avatar" type="nxs:content" />
  <xs:element name="birthdate" type="xs:date" />
  <xs:element name="phonenumber" type="xs:string" />
  <xs:element name="gender" type="xs:boolean" default="false" />
  <xs:element name="locale" type="xs:string" />
</xs:schema>

  "contextParameters": {
    "userprofile": {
      "birthdate": null,
      "phonenumber": null,
      "avatar": null
    }
  }