support for collection shuffle

[colombod]

to go from

var rnd = new Random(42);

var examples = centroids.Select(c => {
    var embedding = c.GetValues().ToArray();
    var reviews = new LinkedList<DataRow>(foodReviewsData
        .ScoreBySimilarityTo(embedding, new CosineSimilarityComparer<float[]>(v => v), r => r.Embedding )
        .OrderByDescending(e => e.Value)
        .Select(e => e.Key)
        .Take(200));

    var samples = new List<DataRow>();
    for(var i = 0; i < 5; i++)
    {
        var sample = reviews.ElementAt(rnd.Next(reviews.Count));
        samples.Add(sample);
        reviews.Remove(sample);
    }
    return new {
            CenstroidEmbedding = embedding,
            Reviews = samples
            };
    }
).ToArray();

to

var examples = centroids.Select(c => {
    var embedding = c.GetValues().ToArray();
    var reviews = new LinkedList<DataRow>(foodReviewsData
        .ScoreBySimilarityTo(embedding, new CosineSimilarityComparer<float[]>(v => v), r => r.Embedding )
        .OrderByDescending(e => e.Value)
        .Select(e => e.Key)
        .Take(200)
        .Shuffle()
        .Take(5));

    return new {
            CenstroidEmbedding = embedding,
            Reviews = examples 
            };
    }
).ToArray();

can see more in the PR azure-samples/openai#63