Validation prevents provider instantiation without an API key

[rorymalcolm]

If you're creating a configuration that's active in some accounts, but not in others, currently you cannot instantiate this provider

provider "openai" {
  admin_key = var.openai_api_key
}

Where var.openai_api_key is null by default - throws an error, in my opinion this should not in fact throw an error as it makes this common config impossible!