Edited the weighted_zonal_gen_dask test to run with Dask
Edited the test_weighted_zonal_gen_dask() function in test_weight_raster_functions.py to run WeightedZonalGen with the dask engine.
Edited the test_weighted_zonal_gen_dask() function in test_weight_raster_functions.py to run WeightedZonalGen with the dask engine.