added gsub to remove <NA values which cause glue errors

[jhawkey]

I recently downloaded all AST data from the NCBI browser.

When I tried to import using this command

import_pheno("data/NCBI_asts_15-07-2026.tsv.gz", format="ncbi")

I got this error:

Error in `mutate()`:
ℹ In argument: `mic = as.mic(mic)`.
Caused by error in `glue()`:
! Expecting 'FCkNXbE-413>'

This was occurring here at the final step in this chunk:

AMRgen/R/import_pheno.R

Lines 533 to 542 in bbeac15

	if ("MIC (mg/L)" %in% colnames(ast)) {
	if ("Measurement sign" %in% colnames(ast)) {
	ast <- ast %>%
	mutate(mic = paste0(`Measurement sign`, `MIC (mg/L)`)) %>%
	mutate(mic = gsub("==", "", mic))
	} else {
	ast <- ast %>% mutate(mic = `MIC (mg/L)`)
	warning("Expected column 'Measurement sign' not found in input, be careful interpreting MIC")
	}
	ast <- ast %>% mutate(mic = as.mic(mic))

Because the function concatenates the measurement sign with the MIC, it was in some instances creating values that looked like <NA. This causes the weird error being thrown by glue(), which creates the warning message telling users what mic values couldn't be converted.

Have added an extra gsub command that turns "<NA" into simply "NA", so that the import can complete.