fwa layers with no features present result in `watershed_group_code` error on `background_layers.sh` build

[NewGraphEnvironment]

+ for layer in '$BCGW_SOURCES'
+ [[ whse_basemapping.fwa_manmade_waterbodies_poly == *\.\f\w\a\_* ]]
+ ogr2ogr -f GPKG background_layers.gpkg -update -t_srs EPSG:3005 -nln whse_basemapping.fwa_manmade_waterbodies_poly -dim XY -where 'watershed_group_code in ('\''ADMS'\'')' whse_basemapping.fwa_manmade_waterbodies_poly.geojson
ERROR 1: "watershed_group_code" not recognised as an available field.
ERROR 1: SetAttributeFilter(watershed_group_code in ('ADMS')) on layer 'whse_basemapping.fwa_manmade_waterbodies_poly' failed.

going to pull from bcdata.txt for now as we are not currently even symbolizing but seems weird....

[NewGraphEnvironment]

tested by building LARL watershed group with the call to that layer included. this will pop up again I'm sure so we should watch for it. Could be any whse_basemapping.fwa_* layer with no features in the area defined by the call to background_layers.sh that will throw this area.

Left this layer in the .txt file as it is nice to have. It is not yet symbolized so will add that as a to do in #110

closing but hopefully will be easy to find with search

[NewGraphEnvironment]

will add the following line to bcdata.sh to remove empty tables

find . -maxdepth 1 -type f -name "*.fwa_*" -size -50c -delete

then in background_layers.sh

get the name of the files (except aoi.geojson) that are left after tiny ones are removed BCGW_SOURCES=$(find . -maxdepth 1 -type f -name "*.geojson" -a '!' -name "aoi.geojson" -exec basename {} .geojson \;)

for glacier fail example can test with

time ./bcdata.sh "'CRKD'" && time ./background_layers.sh "'CRKD'" && time ./qgis_create.sh "new_project_directory"