feat: add UnescapeMappingTemplate to state machine Api event

[hoffa]

Issue #, if available

#1895

Description of changes

Adds UnescapeMappingTemplate boolean to state machine Api event, which unescapes singles quotes in state machine input escaped by escapeJavaScript (which isn't valid JSON).

The final mapping template isn't JSON by design, so can't use json.dumps(). For example:

{"input": "$util.escapeJavaScript($input.json('$')).replaceAll("\\'","'")", "stateMachineArn": "arn:aws:states:us-east-1:792766875239:stateMachine:Post-n7ZKNljUJsZZ"}

Originally done in #2253, but using an opt-in property instead to avoid large-scale redeployments.

Description of how you validated changes

pytest integration --no-cov -k test_state_machine_with_api_single_quotes_input -s
pytest --no-cov samtranslator -n auto tests/translator/test_translator.py -k state_machine_with_api

Checklist

• Add/update unit tests using:
  • Correct values
  • Bad/wrong values (None, empty, wrong type, length, etc.)
  • Intrinsic Functions
• Add/update integration tests
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected
• Do these changes include any template validations?
  • Did the newly validated properties support intrinsics prior to adding the validations? (If unsure, please review Intrinsic Functions before proceeding).
    • Does the pull request ensure that intrinsics remain functional with the new validations?

Examples?

Please reach out in the comments, if you want to add an example. Examples will be
added to sam init through https://github.com/awslabs/aws-sam-cli-app-templates/

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.51%. Comparing base (e7a1496) to head (1bd1d4f).
Report is 1099 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2495      +/-   ##
===========================================
+ Coverage    93.58%   94.51%   +0.93%     
===========================================
  Files           90       97       +7     
  Lines         6124     7311    +1187     
  Branches      1260     1526     +266     
===========================================
+ Hits          5731     6910    +1179     
- Misses         183      193      +10     
+ Partials       210      208       -2     

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[hawflau]

Probably a very rare use case - If this is a Fn::If, the new behavior will be used regardless (as SAM-T can't/doesn't resolve Fn::If). Is that wanted?

We had a similar discussion for PassthroughCondition under DeploymentPreference in #1578

[hoffa]

Doesn't

        "UnescapeMappingTemplate": PropertyType(False, is_type(bool)),

already guarantee it's a bool?

Edit: for posterity, no. We've deprecated PropertyType since it's a footgun and we don't need to resolve intrinsics anymore.

[hawflau]

Can we add something similar to this so we will log the request too?

This will help us investigate in case of flaky test runs