Client method for returning the configuration information and metadata of the specified user pool app client.
cognitoidentityprovider_describe_user_pool_client(UserPoolId, ClientId)
[required] The user pool ID for the user pool you want to describe.
[required] The app client ID of the app associated with the user pool.
svc$describe_user_pool_client( UserPoolId = "string", ClientId = "string" )