feat(interactive): Optimize Path Expand Operator in GIE CBO Optimizer

Given user-specified start and end points for path_expand, like:
```
g.V().hasId(XX).both('1..5').endV().hasId(XX)...
```
This query can be optimized to execute in a manner that traverses from both ends towards the middle. Support for the issue can be provided in two key aspects:
- [ ] The optimizer needs to enumerate various combinations for path_expand splits.
- [ ] Glogue is required to perform cardinality estimation based on the path_expand operator.