Replace ag land counts of None with 0.0
Replace ag land counts of None with 0.0

- update SQL to return 0.0 if original values are None

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