heal: Decode object name in healing result (#11348)

The user can see __XLDIR__ prefix in mc admin heal when the command
heals an empty object with a trailing slash. This commit decodes the
name of the object before sending it back to the upper level.

cmd/erasure-server-pool.go

@@ -1404,6 +1404,7 @@ func (z *erasureServerPools) HealObject(ctx context.Context, bucket, object, ver
 
 	for _, pool := range z.serverPools {
 		result, err := pool.HealObject(ctx, bucket, object, versionID, opts)
+		result.Object = decodeDirObject(result.Object)
 		if err != nil {
 			if isErrObjectNotFound(err) || isErrVersionNotFound(err) {
 				continue