EST parser and Cedar parser return different ASTs on policies with functions named "unknown"

[vasumv]

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Bug Category

Cedar Parser

Describe the bug

The following policy EST fails this check in convert-policy-json-to-cedar.

{
    "effect": "permit",
    "principal": {  "op": "All"  },
    "action": {  "op": "All"   },
    "resource": {  "op": "All"  },
    "conditions": [
        {
            "kind": "when",
            "body": {
                "unknown": [
                    {
                        "Value": ""
                    }
                ]
            }
        }
    ]
}

This is due to the difference in AST expression kind built when parsing the EST (Unknown) vs parsing Cedar (ExtensionFunctionApp).

Also related to #891

Expected behavior

.

Reproduction steps

.

Code Snippet

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Log output

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Additional configuration

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Operating System

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Additional information and screenshots

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