Fix null reference exception on Exif clone of null ExifArrayValue

src/ImageSharp/Metadata/Profiles/Exif/Values/ExifValue.cs

@@ -29,7 +29,7 @@ internal ExifValue(ExifValue other)
             {
                 // All array types are value types so Clone() is sufficient here.
                 var array = (Array)other.GetValue();
-                this.TrySetValue(array.Clone());
+                this.TrySetValue(array?.Clone());
             }
         }
 

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.Metadata.cs

@@ -302,6 +302,19 @@ public void Decode_WithInvalidIptcTag_DoesNotThrowException<TPixel>(TestImagePro
             Assert.Null(ex);
         }
 
+        [Theory]
+        [WithFile(TestImages.Jpeg.Issues.ExifNullArrayTag, PixelTypes.Rgba32)]
+        public void Clone_WithNullRationalArrayTag_DoesNotThrowException<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : unmanaged, IPixel<TPixel>
+        {
+            Exception ex = Record.Exception(() =>
+            {
+                using Image<TPixel> image = provider.GetImage(JpegDecoder);
+                var clone = image.Metadata.ExifProfile.DeepClone();
+            });
+            Assert.Null(ex);
+        }
+
         [Fact]
         public void EncodedStringTags_WriteAndRead()
         {

tests/ImageSharp.Tests/TestImages.cs

@@ -262,6 +262,7 @@ public static class Issues
                 public const string MalformedUnsupportedComponentCount = "Jpg/issues/issue-1900-malformed-unsupported-255-components.jpg";
                 public const string MultipleApp01932 = "Jpg/issues/issue-1932-app0-resolution.jpg";
                 public const string InvalidIptcTag = "Jpg/issues/Issue1942InvalidIptcTag.jpg";
+                public const string ExifNullArrayTag = "Jpg/issues/issue-2056-exif-null-array.jpg";
 
                 public static class Fuzz
                 {