amp_heatmap with more than one level to tax_add errors

[KasperSkytte]

library("ampvis2")
#> Loading required package: ggplot2
amp_heatmap(
  AalborgWWTPs,
  tax_aggregate = "Genus",
  tax_add = c("Phylum", "Class")
)
#> Error in if (tax_add != tax_aggregate) {: the condition has length > 1

^{Created on 2022-10-13 by the reprex package (v2.0.1)}