Put in checks for empty/bad geometry in all SGCN data collection scripts

[memoore]

Don't know how to do this in R, but features in the PGC bat dataset with empty geometry were causing downstream problems.

[ChristopherTracey]

This post has some tips: https://www.r-spatial.org/r/2017/03/19/invalid.html

st_dimension() seems to be the easiest way to check. Not sure about how to fix yet.