[2pt] Add backpool_stats.csv to the deny lists

[CarsonPruitt-NOAA]

I noticed in our HAND v4.5.11.1 outputs that there is a new file that should probably be removed from the saved pipeline results. Please add backpool_stats.csv to the appropriate deny lists.

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Update. Merge 1330 into this Issue and closed it.
Tasks from that one;

A bit of cleanup with the deny lists.
Update deny_unit.list

• uncomment- nwm_subset_streams_levelPaths_dissolved_headwaters.gpkg
• add nwm_headwater_points_subset.gpkg (not there and leave off the pound sign
• uncomment branch_polygons.gpkg

Update deny_branch_zero.list

• uncomment - gw_catchments_reaches_filtered_addedAttributes_{}.gpkg