[webp]animated webp image became static after processing

Prerequisites

[X] I have written a descriptive issue title
[X] I have verified that I am running the latest version of ImageSharp
[X] I have verified if the problem exist in both DEBUG and RELEASE mode
[X] I have searched open and closed issues to ensure it has not already been reported

ImageSharp version

3.0.1

Other ImageSharp packages and versions

SixLabors.ImageSharp.Drawing(1.0.0)

Environment (Operating system, version and so on)

Win10 22H2

.NET Framework version

.NET 6

Description

mathiasbynens.be/demo/animated-webp-supported.webp cannot load animated webp images or save one correctly. Maybe the method I used is wrong. Really appreciate for your work~

Steps to Reproduce

1.download the example image 2.load with code

            using (var imgStream = new MemoryStream())
            {
                await Request.Body.CopyToAsync(imgStream);
                if (imgStream == null || imgStream.Length == 0)
                {
                    return Fail("image can not be null");
                }
               var  buffer = new byte[imgStream.Length];
                imgStream.Position = 0;
                await imgStream.ReadAsync(buffer, 0, buffer.Length);
                //using(Image img=Image.Load(file))  //At first i wrote this line which turned out img.Frames.Count=1
                using (Image img = Image.Load(new DecoderOptions { MaxFrames = 100 }, file))//this way turned out img.Frames.Count=12
                {
                            var filePath= AppContext.BaseDirectory + Guid.NewGuid().ToString() + ".webp";
                            await img.SaveAsync(filePath);
                }
            }

Images

68747470733a2f2f6d61746869617362796e656e732e62652f64656d6f2f616e696d617465642d776562702d737570706f727465642e77656270.zip

SixLabors / ImageSharp

[webp]animated webp image became static after processing #2521