keycloak_authentication_execution_config on first broker login fails against V21 onwards

[Marcus-James-Adams]

We did have the following code working ok on v19

# Disable the prompt to enter user details at the first login
# -----------------------------------------------------------

data "keycloak_authentication_flow" "first_broker_login" {
  realm_id = keycloak_realm.realm.id
  alias    = "first broker login"
}

data "keycloak_authentication_execution" "first_broker_login" {
  realm_id          = keycloak_realm.realm.id
  parent_flow_alias = data.keycloak_authentication_flow.first_broker_login.alias
  provider_id       = "idp-review-profile"
}

resource "keycloak_authentication_execution_config" "first_broker_login" {
  realm_id     = keycloak_realmrealm.id
  execution_id = data.keycloak_authentication_execution.first_broker_login.id
  alias        = "review profile config"
  config = {
    "update.profile.on.first.login" = "off"
  }
}

however, since upgrading to V21 when creating a new environment we now get the following errors

keycloak_authentication_execution_config.first_broker_login: Creating...
╷
│ Error: error sending POST request to /auth/admin/realms/myrealm/authentication/executions/57a5c4ef-7bfc-4121-ab6d-72583f1d54a9/config: 409 Conflict. Response body: {"error":"unknown_error"}
│
│   with keycloak_authentication_execution_config.first_broker_login,
│   on keycloak.realm.tf line 119, in resource "keycloak_authentication_execution_config" "first_broker_login":
│  119: resource "keycloak_authentication_execution_config" "first_broker_login"

[kherock]

This is a duplicate of #839, and fixed by #840!