[REST source] header_links can extract from responses without a records_path

[willi-mueller]

Tell us what you do here

• [x] fixing a bug (please link a relevant bug report)

Relevant issue

issue #313

More PR info

Before: responses without the necessity for a records_path such as [{"id": 0, "attr": "foobar"}] caused the following exception with the header_links paginator :

  File "rest_api/client.py", line 148, in paginate
    yield extract_records(response)
          ^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'NoneType' object is not callable

Before

After

[burnash]

Brilliant! Thanks @willi-mueller!