fix(logging): Don't include json_default in logs

[michaelbrewer]

Issue #, if available:

Currently given a custom json_default with the Logger When we log out message Then we include the json_default in the log message:

>>> logger = Logger(level="DEBUG", stream=stdout, json_default=lambda o: f"<non-serializable: {type(o).__name__}>")
>>> logger.debug({"x": Unserializable()})
{'timestamp': '2020-08-25 11:55:27,114', 'level': 'DEBUG', 'location': 'test:112', 'service': 'service_undefined', 'sampling_rate': 0.0, 'json_default': '<non-serializable: function>', 'message': {'x': '<non-serializable: Unserializable>'}}

The output should exclude json_default:

>>> logger = Logger(level="DEBUG", stream=stdout, json_default=lambda o: f"<non-serializable: {type(o).__name__}>")
>>> logger.debug({"x": Unserializable()})
{'timestamp': '2020-08-25 11:59:27,962', 'level': 'DEBUG', 'location': 'test:112', 'service': 'service_undefined', 'sampling_rate': 0.0, 'message': {'x': '<non-serializable: Unserializable>'}}

Description of changes:

• formatter.py - pop json_default from the **kwargs before updating self.format_dict
• formatter.py - clean up and remove uneeded pragma: no cover
• formatter.py - remove unused decode case
• test_aws_lambda_logging.py - update unit tests to include a check for json_default
• general - clean up to please sonarlint

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Merging #132 into develop will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##           develop      #132   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           24        24           
  Lines          706       706           
  Branches        66        67    +1     
=========================================
  Hits           706       706           

Impacted Files	Coverage Δ
aws_lambda_powertools/logging/formatter.py	100.00% <100.00%> (ø)

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[heitorlessa]

Thanks a lot Mike!!

[heitorlessa]

LGTM