google_container_cluster: add support for new GKE Gateway API controller

[modular-magician]

Fixed hashicorp/terraform-provider-google#13117

If you want to use the new Gateway API Controller inside your GKE clusters you need to be able to define a channel to be used. By default no channel is selected, therefore the GKE Gateway Controller does not install the necessary CRDs and the GatewayClasses.

Gateway API Documentation: https://cloud.google.com/kubernetes-engine/docs/concepts/gateway-api
SDK Documentation: https://cloud.google.com/sdk/gcloud/reference/container/clusters/create#--gateway-api
GOlang Reference: https://pkg.go.dev/google.golang.org/api/container/v1#GatewayAPIConfig

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Release Note Template for Downstream PRs (will be copied)

container: added `gateway_api_config` block to `google_container_cluster` resource for supporting the gke gateway api controller

Derived from GoogleCloudPlatform/magic-modules#6875