Policy JSON format does not error for spaces in annotations

[john-h-kastner-aws]

Before opening, please confirm:

• I have searched for duplicate or closed issues.
• I have read the guide for submitting bug reports.
• I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.

Bug Category

Cedar Parser

Describe the bug

The following policy is accepted by the JSON policy parse, but it defines an annotation containing a space, which is not possible in the Cedar policy syntax. The JSON policy parser should instead return an error.

{
    "annotations": {
      " ": ""
    },
    "effect": "permit",
    "principal": { "op": "All" },
    "action": { "op": "All" },
    "resource": { "op": "All" },
    "conditions": [ ]
}

The most straightforward fix is to check for spaces in annotations in try_into_ast_template.