TF Resource auth0_connection missing options.attributes to support new Connection Attributes (Flexible Identifiers)

[chrishaynes21]

Checklist

• I agree to the terms within the Auth0 Code of Conduct.

Describe the problem you'd like to have solved

We manage our various Auth0 tenants via Terraform. However, the new attributes feature on database connections doesn't have an option to be enabled and configured via Terraform. I've poured over the schema for the resource auth0_connection v1.4.0, and the closest I can find is the options.attributes_map.attributes, but that appears to be for mapping incoming fields from external IdPs, not database connections.

Describe the ideal solution

Add support for attributes in the options object in the TF connection resource, since it is already in the API.

{
        "attributes": {
            "email": {
                "signup": {
                    "status": "required",
                    "verification": {
                        "active": true
                    }
                },
                "identifier": {
                    "active": true
                },
                "profile_required": true
            }
        },
}

Alternatives and current workarounds

We can click around the UI, but it's better for us to audit changes via code.

Additional context

No response

[timgates42]

@chrishaynes21 I believe this PR adds support for what you are after #991