fix referenced components removed in openapi schema

[AndrewFossAWS]

Issue #, if available:

Customer reported referenced component being removed in openapi schema.

In RemoveUnusedComponents, it only keeps referenced components if the field object size is 1.

However there are cases where the field object size is greater than 1.

For example:

smithy:

structure OperationInput {
    @default({})
    payload: StringMap
}

map StringMap {
    key: String
    value: String
}

openapi:

(StringMap is removed in the schemas object.)

    "schemas": {
        "OperationRequestContent": {
            "properties": {
                "payload": {
                    "$ref": "#/components/schemas/StringMap",
                    "default": {}
                }
            }
        }
    }

Description of changes:

Remove the field object size check when removing unused components

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

[mtdowling]

I didn't think $ref objects allowed more than one property. Can you confirm?

[AndrewFossAWS]

I didn't think $ref objects allowed more than one property. Can you confirm?

@mtdowling From the reference object section of the OpenAPI spec:

This object cannot be extended with additional properties and any properties added SHALL be ignored.

So default property will be ignored in my example.
I was able to deploy an openapi json with the additional property default to API Gateway. The default property was ignored/removed.

I can add a WARN log to let users know the additional properties will be ignored.

[mtdowling]

Thanks. Warning would be too noisy here since it looks like we add default values to these refs automatically.