[PutRequestResponseSchemeArm] False positive due to bug in utils.isSchemaEqual()

[mikeharder]

In this check run, run PutRequestResponseSchemeArm appears to fail with a false positive, since the schemas are indeed identical. I believe the bug is in helper function utils.isSchemaEqual():

https://github.com/Azure/azure-openapi-validator/blob/edb65591d5ab85871f880e48b2ad6302186014b8/packages/rulesets/src/spectral/functions/utils.ts

Even if the schemas are equal, if one of the property values is null, it will cause isSchemaEqual() to fail, which looks like a bug to me. Unless there's some reason this behavior was chosen intentionally.

[mikeharder]

Another example.

PR: Azure/azure-rest-api-specs#38365
Run: https://github.com/Azure/azure-rest-api-specs/actions/runs/18763997530

Root cause is a property with value null in the spec:

        "sharingScope": {
          "type": "string",
          "default": null,

https://github.com/Azure/azure-rest-api-specs/blob/2b40f1e7eab4de4f94e8bce032f91b25b3656f86/specification/network/resource-manager/Microsoft.Network/stable/2025-01-01/virtualNetwork.json#L1667-L1669