fix: Allow intrinsics in SAM Globals properties

[kddejong]

Issue #, if available

Fixes #4680

Description of changes

Since #4491 the Globals section is validated against globals.json by E3724 (GlobalsTransform). That rule validated the section without enabling intrinsic functions or intrinsic-aware type checking, so any type-constrained Globals property rejected Ref/Fn::ImportValue/Fn::Sub:

E3724 {'Fn::ImportValue': {'Fn::Sub': 'my-iam-${Environment}-lambda-boundary-arn'}} is not of type 'string'

The reporter flagged Function.PermissionsBoundary, but it's broader — e.g. Function.Runtime: !Ref X failed the same way. The same intrinsic on the resource's own Properties was already accepted, so only the Globals path was affected.

Fix: when validating the Globals section, enable functions and use the intrinsic-aware cfn_type, mirroring how resource properties and Outputs values are validated. Malformed literals are still flagged (E3724/E3012), and the merged resource-level validation remains a second layer.

Validated against the real SAM translator (sam validate, aws-sam-translator 1.165.0): it accepts the intrinsic in Globals.Function.PermissionsBoundary and in Globals.Function.Runtime; a non-intrinsic object literal is still rejected by cfn-lint's schema type check.

Testing

• Added regression cases to test/unit/rules/resources/test_globals_transform.py (intrinsic in PermissionsBoundary/Runtime → no error; non-intrinsic object → still errors).
• ruff, ruff format, isort, mypy clean.
• test/unit/rules/resources + test/unit/rules/functions (1482) and serverless integration tests pass.

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.64%. Comparing base (9c6ecc9) to head (48c6720).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4683   +/-   ##
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  Coverage   94.64%   94.64%           
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  Files         433      433           
  Lines       15511    15512    +1     
  Branches     3011     3011           
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+ Hits        14681    14682    +1     
  Misses        453      453           
  Partials      377      377           

Flag	Coverage Δ
unittests	94.64% <100.00%> (+<0.01%)	⬆️

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