`konnect_gateway_key` resource has perpetual diff when JWK is used

There seems to be diff due to whitespace for `jwk` field - happens with or without `jsonencode`

<img width="628" height="82" alt="Image" src="https://github.com/user-attachments/assets/eab37a40-865e-479c-a329-e53bf2fb8704" />