Fix rendering of tap response from XOS

[sentry-io]

Sentry Issue: SPOTLIGHTS-3

TypeError: Object of type bytes is not JSON serializable
(11 additional frame(s) were not displayed)
...
  File "__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "json/encoder.py", line 201, in encode
    chunks = list(chunks)
  File "json/encoder.py", line 438, in _iterencode
    o = _default(o)
  File "flask/json/__init__.py", line 100, in default
    return _json.JSONEncoder.default(self, o)
  File "json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '

[hvanness]

Closing as a duplicate of #56