Trying to load child datasets fails when there are none

See the only dataset in https://stirdata.opendata.cz Config (xrg12):

dcat-ap-viewer:
  version: 2
  # Port used for dcat-ap-viewer.
  port: 3000
  # Set to true if you want dcat-ap-viewer to serve static content from
  # "dist" directory. After "npm run build" this directory contains HTML, CSS,
  # JavaScript and other static files. This value should be set to false in
  # a production and static content should be server by other application
  # like Nginx. For more information how visit
  # https://github.com/linkedpipes/dcat-ap-viewer/wiki/Let's-deploy-to-production
  serve-static-content: true
  providers:
  # For more information about providers and their configuration please
  # see https://github.com/linkedpipes/dcat-ap-viewer/wiki/Providers.
    - type: solr
      # Path to the Solr instance, including solr core.
      url: http://localhost:8983/solr/dcat-ap-viewer
      # Default API language.
      default-language: cs
      # List of all languages in Solr.
      languages:
        - cs
        - en
    - type: couchdb
      # Address of
      url: http://127.0.0.1:5984
      # Default API language.
      default-language: cs
    - type: sparql
      # SPARQL endpoint.
      url: http://localhost:8890/sparql
      # We use SPARQL endpoint only for quality related data.
      filter:
        - v2-quality
  client:
    # Name of a profile directory within ./client/ directory.
    # Read readme file in the profile directory to get more information
    # about following options.
    profiles:
      - profile-lkod
    page-title-default: "STIRData catalog"
    page-title-prefix: ""
    page-title-suffix: " - STIRData catalog"
    url-base: "https://stirdata.opendata.cz/"

linkedpipes / dcat-ap-viewer

Trying to load child datasets fails when there are none #235