NormalizedMetadata is not Identifiable

Implement a private record to use metadata after changes in:
opendaylight/yangtools@6371872

JIRA: LIGHTY-235
Signed-off-by: tobias.pobocik <tobias.pobocik@pantheon.tech>

lighty-modules/lighty-netconf-sb/src/main/java/io/lighty/modules/southbound/netconf/impl/NetconfNmdaBaseServiceImpl.java

@@ -229,7 +229,7 @@ private NormalizedMetadata leafMetadata(YangInstanceIdentifier path, final Effec
 
         // Step one: open builders
         for (PathArgument arg : args) {
-            builders.push(ImmutableNormalizedMetadata.builder().withIdentifier(arg));
+            builders.push(new BuilderEntry(arg, ImmutableNormalizedMetadata.builder()).builder());
         }
 
         // Step two: set the top builder's metadata
@@ -277,4 +277,10 @@ private ChoiceNode getFilterSpecChoiceNode(final YangInstanceIdentifier filterYI
                 .withChild(subtreeFilter)
                 .build();
     }
+    private record BuilderEntry(PathArgument identifier, ImmutableNormalizedMetadata.Builder builder) {
+        BuilderEntry {
+            requireNonNull(identifier);
+            requireNonNull(builder);
+        }
+    }
 }