Error caused by newly introduced NA columns in GMS Wahlrecht table

[bauer-alex]

coalitions::get_surveys()

leads to Error in `[.data.frame`(atab, , !ind.empty) : undefined columns selected.
This is caused by the latest update of Wahlrecht's GMS table, which now leads to two trailing NA columns in the following dataset:

atab <- read_html(address) %>%
html_nodes("table") %>% .[[2]] %>%
html_table(fill = TRUE)

However, scrape_wahlrecht() currently cannot handle such NA columns.