state: fix nil dereference when an afterLoad method fails

The following call to Failf() uses ods expecting it to be the failed
objectDecodeState.

PiperOrigin-RevId: 822203784

Author: nixprime

pkg/state/decode.go

@@ -694,6 +694,7 @@ func (ds *decodeState) Load(obj reflect.Value) {
 	// iterations required to finish all objects.
 	if err := safely(func() {
 		for elem := ds.leaves.Front(); elem != nil; elem = elem.Next() {
+			ods = elem.ods
 			ds.checkComplete(elem.ods)
 		}
 	}); err != nil {