fix: Traversal.graph is empty in StepStrategy.apply() with `count().i…

…s(0)`

This PR fix: traversal.getGraph() is empty in StepStrategy.apply() method
    `VertexStepStrategy.apply(Traversal.Admin<?, ?> traversal)`
for the following gremlin:
```
    g.V(3).repeat(inE('child').outV().simplePath())
      .until(or(inE().count().is(0),loops().is(eq(2))))
      .path()
```

gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/strategy/optimization/CountStrategy.java

@@ -164,6 +164,7 @@ public void apply(final Traversal.Admin<?, ?> traversal) {
                                 } else {
                                     inner = __.identity().asAdmin();
                                 }
+                                traversal.getGraph().ifPresent(graph -> inner.setGraph(graph));
                                 if (prev != null)
                                     TraversalHelper.replaceStep(prev, new NotStep<>(traversal, inner), traversal);
                                 else