Error when a client tries to close the connection and the server is already closed

[redDwarf03]

Describe the problem you discovered

When a Dapp tries to close a connection to the Wallet and the server is not active (for example because the user close manually the RPC Server), an error occurs in the websocket class

  @override
  Future<void> close() async {
    await _client?.close();
    _client = null;
  }

WebSocketChannelException (WebSocketChannelException: WebSocketChannelException: SocketException: Connection refused (OS Error: Connection refused, errno = 61), address = 127.0.0.1, port = 51367)

Describe the solution you'd like

Manage the case where the server's connection is already closed when we try to close client connection

Epic

No response