fix: S3 HeadObject NotFound error never being returned (#2139)

Author: aajtodd

.changelog/d9de6f3dd7c146c9966648ecda1fa2a8.json

@@ -0,0 +1,8 @@
+{
+    "id": "d9de6f3d-d7c1-46c9-9666-48ecda1fa2a8",
+    "type": "bugfix",
+    "description": "Fix HeadObject to return types.Nound when an object does not exist. Fixes [2084](https://github.com/aws/aws-sdk-go-v2/issues/2084)",
+    "modules": [
+        "service/s3"
+    ]
+}

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/customization/S3HeadObjectCustomizations.java

@@ -32,7 +32,6 @@ software.amazon.smithy.aws.go.codegen.customization.S3AcceptEncodingGzip
 software.amazon.smithy.aws.go.codegen.customization.KinesisCustomizations
 software.amazon.smithy.aws.go.codegen.customization.S3ErrorWith200Status
 software.amazon.smithy.aws.go.codegen.customization.Route53Customizations
-software.amazon.smithy.aws.go.codegen.customization.S3HeadObjectCustomizations
 software.amazon.smithy.aws.go.codegen.customization.PresignURLAutoFill
 software.amazon.smithy.aws.go.codegen.customization.S3ExportInternalFeatures
 software.amazon.smithy.aws.go.codegen.customization.S3ControlEndpointResolver