NatsWebSocketOpts improvements

[mtmk]

A couple more ideas, which could be done in a follow-up before releasing:

1. Do we want to nest this option under NatsWebSocketOpts instead of setting it directly in NatsOpts? This could make it easier to offer a shortcuts for popular options such as adding headers:

public sealed record NatsWebSocketOpts
{
    public Dictionary<string, StringValues>? RequestHeaders { get; init; }

    public Func<Uri, ClientWebSocketOptions, CancellationToken, ValueTask>? ConfigureWebSocketOptions { get; init; }
}

2. We probably want to invoke NatsTlsOpts.AuthenticateAsClientOptionsAsync and copy both ClientCertificates and RemoteCertificateValidationCallback to ClientWebSocketOptions prior to passing it to the callback

Originally posted by @caleblloyd in #605 (comment)

[Ivandemidov00]

Hi guys.
I can make these changes. Do I understand correctly that we need to wait first #605 ?

[mtmk]

Hi guys. I can make these changes. Do I understand correctly that we need to wait first #605 ?

thanks @Ivandemidov00 that would be great 👍💯 please tag @caleblloyd in your PR so he can review when he has time ;)

edit: btw #605 is merged in case you missed it.