fix(s3): fix check in dedupe logic (#2700)

cache.HasBlob() looks in both buckets: duplicates and original blobs
Because we want to check if the blob is in original bucket let's use
cache.GetBlob() because it's looking only in original bucket.

Signed-off-by: Eusebiu Petu <petu.eusebiu@gmail.com>

pkg/storage/imagestore/imagestore.go

@@ -1930,7 +1930,7 @@ func (is *ImageStore) dedupeBlobs(ctx context.Context, digest godigest.Digest, d
 				}
 
 				// cache original blob
-				if ok := is.cache.HasBlob(digest, originalBlob); !ok {
+				if _, err := is.cache.GetBlob(digest); err != nil {
 					if err := is.cache.PutBlob(digest, originalBlob); err != nil {
 						return err
 					}