LeakIX handle HTTP 204 response

[zcrt]

LeakIX API responses with scope=leak where there are no results for the query tend to return an empty HTTP 204 response.

Calling .json() on an empty 204 response, as is done in the LeakIX boefje, results in a JSONDecodeError making the boefje fail.

[ERROR] [runner] Error while running boefje module leakix[2e423ae3d7bb4207a458ee4e347b22bd]
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/requests/models.py", line 971, in json
    return complexjson.loads(self.text, **kwargs)
  File "/usr/local/lib/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/usr/local/lib/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/local/lib/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/app/boefjes/boefjes/runner.py", line 74, in run
    self.boefje_meta, output = self.boefje_resource.module.run(
  File "/app/boefjes/boefjes/plugins/kat_leakix/main.py", line 36, in run
    response_json = response.json()
  File "/usr/local/lib/python3.8/site-packages/requests/models.py", line 975, in json
    raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

This pull request proposes a quick fix for this by avoiding the .json() call on a requests object where the content is empty.

[ammar92]

No remarks!