Adapt to change in Gerrit core

Change-Id: I52ed6e72dde828cb4d90dea2e4479c45d7597d21
diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
index cae071a..2ccf33b 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
@@ -264,10 +264,10 @@
       } else if (a.isLegacySubmit()) {
         submit = a;
       } else {
-        LabelType type = labelTypes.byLabel(a.labelId());
-        if (type != null) {
+        Optional<LabelType> type = labelTypes.byLabel(a.labelId());
+        if (type.isPresent()) {
           fmt.appendApproval(
-              type,
+              type.get(),
               a.value(),
               a.accountId(),
               accountCache.get(a.accountId()).map(AccountState::account));