Describe the bug

When using GenerativeAIEmbeddingGenerator with the model models/gemini-embedding-001, the Dimensions property in EmbeddingGenerationOptions seems to be ignored.

I explicitly set the Dimensions to 1536, but the generated embedding vector length returned is 3072.

To Reproduce

Run the following C# code snippet:

var key = "YOUR_API_KEY"; // Replaced for security
var options = new EmbeddingGenerationOptions()
{
    Dimensions = 1536
};

var generator = new GenerativeAIEmbeddingGenerator(key, "models/gemini-embedding-001");
var result = await generator.GenerateAsync(["testtest"], options);
var embedding = result[0].Vector;

Console.WriteLine($"Expected Length: {options.Dimensions}");
Console.WriteLine($"Actual Length: {embedding.Length}"); 
// Actual output is 3072

Expected behavior

The length of the returned embedding array (embedding.Length) should be 1536, matching the configured Dimensions option.

Actual behavior

The length of the returned embedding array is 3072.

Environment

• Version: 3.4.1