Fixed server-side exception handling

[yallie]

See issue #69. Server class:

public class TestService : ITestService
{
	public void Error(string message) => throw new Exception(message);
}

Usage:

using var client = new RemotingClient(new ClientConfig()
{
    ConnectionTimeout = 5,
    InvocationTimeout = 5,
    SendTimeout = 5,
    MessageEncryption = false,
    ServerPort = _serverFixture.Server.Config.NetworkPort
});

client.Connect();

var proxy = client.CreateProxy<ITestService>();

// the call times out and throws a TimeoutException instead of the expected Exception
var ex = Assert.Throws<Exception>(() => proxy.Error("Message"));