Convert managed policy names in intrinsic if values

[francilioaraujo]

Issue #, if available

#3874

Description of changes

Added a new condition that converts managed policy names in intrinsic if values. I also had to refactor construct_role_for_resource to decrease the number of branches (the lines that build policies inside ifs).

Description of how you validated changes

Added tests to validate four cases:

• When finding managed policy names in Policies
• When finding an unknown policy name in Policies
• When finding an intrinsic if, with a managed policy name as value if true and AWS::NoValue as value if false
• When finding an intrinsic if, with AWS::NoValue as value if true and a managed policy name as value if false

Checklist

• Review the generative AI contribution guidelines
• Adheres to the development guidelines
• Add/update transform tests
  • Using correct values
  • Using wrong values
• Add/update integration tests

Examples?

Please reach out in the comments if you want to add an example. Examples will be
added to sam init through aws/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.