fix old copy paste issue

Author: Sven Claesson

tests/ImageSharp.Tests/Formats/ImageFormatManagerTests.cs

@@ -43,7 +43,7 @@ public void IfAutoLoadWellKnownFormatsIsTrueAllFormatsAreLoaded()
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<PngDecoder>().Count());
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<BmpDecoder>().Count());
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<JpegDecoder>().Count());
-        Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<BmpDecoder>().Count());
+        Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<GifDecoder>().Count());
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<TgaDecoder>().Count());
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<TiffDecoder>().Count());
         Assert.Equal(1, this.DefaultFormatsManager.ImageDecoders.Select(item => item.Value).OfType<WebpDecoder>().Count());