fix(logger): ensure state is cleared for custom formatters

[heitorlessa]

Issue #, if available: #1042

Description of changes:

This ensures custom logger formatters receive Lambda context keys and their state can be cleared upon each invocation when using clear_state. This PR also takes into account those using log_record_order with custom formatters, if the state is ever cleared.

The reason we use an abstractmethod is to ensure all functionalities (as docs suggested) will work for the ~1% of customers creating highly customized loggers that can work in more than Lambda environments. We initially thought in having warnings but given this is a bug behavior and the extreme edge case, it makes it worthwhile to enforce it early and improve documentation on use cases for LambdaPowertoolsFormatter (common, no change required) vs BasePowertoolsFormatter (edge case).

Checklist

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

Breaking change checklist

RFC issue #:

• Migration process documented
• Implement warnings (if it can live side by side)

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 #1072 (7c44ba8) into develop (22f8b9a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 7c44ba8 differs from pull request most recent head 124a19b. Consider uploading reports for the commit 124a19b to get more accurate results

@@           Coverage Diff            @@
##           develop    #1072   +/-   ##
========================================
  Coverage    99.96%   99.96%           
========================================
  Files          119      119           
  Lines         5365     5373    +8     
  Branches       612      613    +1     
========================================
+ Hits          5363     5371    +8     
  Partials         2        2           

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

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