[AI] Navmesh does not get built inside of navmesh bounds that is in a non-activated data layer

WP navmesh generation does not appear to work if a navmesh bounds volume is in a data layer. The navmesh will build if the data layer is activated when the build paths is started, but it will not load/unload with the data layer.

If you attempt this in a small level such as the third person template level, you can separate the navmesh bounds into the data layer and it will build navmesh in the two distinct bounds if you build with the data layer unloaded. 

1. Create a new level using the Open World template
2. Add a navmesh bounds volume to the level on one side of the map
3. Enlarge the navmesh bounds volume to be roughly 25% of the map
4. Duplicate (or add) the navmesh bounds volume and place it on the other half of the level with no overlap between the two navmesh bounds volumes
5. Create a Data Layer and call it Navmesh
6. In data layers, add one of the navmesh bounds volumes to the data layer
7. Set the data layer to be activated at runtime
8. Unload the data layer
9. Setup navmesh for use in world partition as noted in the official docs
10. Build paths
11. Activate the navmesh data layer

Expected Result:

Navmesh has been built inside the navmesh data layer's bounds volume.

Actual Result:

No navmesh was built in the data layer's bounds volume, but it is built for the other bounds volume.