QA/QC tool fails is there is no data in dataframes expected to contain geocoordinates

We need to trap cases where site, field, soi or weather sheets have no data. Currently, this error appears when the script attempts to rename variables for a given df containing coordinates:
Error in `$<-.data.frame`(`*tmp*`, Source, value = "S1. Soil Meta") :
replacement has 1 row, data has 0

In this specific case, the problem was with the soil metadata:
S1Soils <- S1__Soil_Metadata[ , c("Soil ID", "Latitude", "Longitude")]
S1Soils$Source <- "S1. Soil Meta"

Start with the QA/QC tool and the S1Soils construction shown in the issue, then trace how site, field, soi, and weather sheets are handled when empty. Reproduce an empty data frame and confirm the tool traps the case without the replacement-row error for each sheet type.

Written by the indexing model from the issue text.