Issue with Hateoas Provider

[asifgis]

Description

earth-data:
        type: stac-collection
        title: OOC_Cubes_and_clouds
        id: OOC_Cubes_and_clouds
        description: Cubes and Clouds catalog for course submissions
        providers:
            - type: stac
              name: Hateoas
              data: https://esa.pages.eox.at/cubes-and-clouds-catalog/MOOC_Cubes_and_clouds
              file_types: catalog.json
        links: 
            -
earth-data-Not-working:
        type: stac-collection
        title: OOC_Cubes_and_clouds-not-working
        id: OOC_Cubes_and_clouds-not-working
        description: Cubes and Clouds catalog for course submissions not working
        providers:
            - type: stac
              name: Hateoas
              data: https://esa.pages.eox.at/cubes-and-clouds-catalog/MOOC_Cubes_and_clouds
              file_types: catalog.json            

Links in yaml configuration is mandatory. Please check the above examples one is working with links and other without links. Without links in the config generate the below error.

  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 1488, in __call__
    return self.wsgi_app(environ, start_response)
  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 1466, in wsgi_app
    response = self.handle_exception(e)
  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 1463, in wsgi_app
    response = self.full_dispatch_request()
  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 872, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 870, in full_dispatch_request
    rv = self.dispatch_request()
  File "d:\flask_app_geoapi\pygeoapi\.venv\lib\site-packages\flask\app.py", line 855, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
  File "D:\flask_app_geoapi\pygeoapi\pygeoapi\flask_app.py", line 482, in stac_catalog_path
    return get_response(api_.get_stac_path(request, path))
  File "D:\flask_app_geoapi\pygeoapi\pygeoapi\api.py", line 228, in inner
    headers, status, content = func(*args, **kwargs)
  File "D:\flask_app_geoapi\pygeoapi\pygeoapi\api.py", line 210, in inner
    return func(cls, req_out, *args[2:])
  File "D:\flask_app_geoapi\pygeoapi\pygeoapi\linked_data.py", line 60, in inner
    return func(*args, **kwargs)
  File "D:\flask_app_geoapi\pygeoapi\pygeoapi\api.py", line 3957, in get_stac_path
    content['links'].extend(stac_collections[dataset]['links'])
KeyError: 'links'

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• OS:
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• pygeoapi version:

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