Fix DRB detection for stream delineation feature.
Fix DRB detection for stream delineation feature.

* DRB is not a boundary layer, but a stream layer. This worked
previously because of this bug:
https://github.com/WikiWatershed/model-my-watershed/pull/1218

project-icp/bee-pollinator-app,kdeloach/model-my-watershed,kdeloach/model-my-watershed,kdeloach/model-my-watershed,WikiWatershed/model-my-watershed,WikiWatershed/model-my-watershed,project-icp/bee-pollinator-app,WikiWatershed/model-my-watershed,project-icp/bee-pollinator-app,WikiWatershed/model-my-watershed,project-icp/bee-pollinator-app,kdeloach/model-my-watershed,kdeloach/model-my-watershed,WikiWatershed/model-my-watershed