fix: allow payload verification error to be returned (#15364)

without reading the reader the error is ignored
by the custom unmarshaller written by ObjectLegalHold
data structure.

buildscripts/race.sh

@@ -3,6 +3,8 @@
 set -e
 
 export GORACE="history_size=7"
+export MINIO_API_REQUESTS_MAX=10000
+
 ## TODO remove `dsync` from race detector once this is merged and released https://go-review.googlesource.com/c/go/+/333529/
 for d in $(go list ./... | grep -v dsync); do
     CGO_ENABLED=1 go test -v -race --timeout 100m "$d"