refdb_clean_seq_crop_primers returns NA if one primer is not found

[FabianRoger]

refdb_clean_seq_crop_primers returns NA if one primer is not found:

repex:

primer_F <- paste0(rep("A",20), collapse = "")
primer_R <- paste0(rep("T",20), collapse = "")
SEQ <- paste0(rep("CG",10), collapse = "")

seq_w_F <- paste0(primer_F, SEQ, collapse = "")
seq_w_R <- paste0(SEQ, primer_R, collapse = "")
seq_FR <- paste0(primer_F, SEQ, primer_R, collapse = "")

test <- 
tibble(primer = c("seq_w_F",
                  "seq_w_R",
                  "seq_FR",
                  "seq_noP"),
         sequence = c(seq_w_F,
                      seq_w_R,
                      seq_FR,
                      SEQ)) %>% 
  refdb_set_fields(sequence = "sequence")


refdb_clean_seq_crop_primers(test,
                             primer_F,
                             primer_R,
                             include_primers = F)

this results in

 primer  sequence            
  <chr>   <DNA>               
1 seq_w_F NA                  
2 seq_w_R NA                  
3 seq_FR  CGCGCGCGCGCGCGCGCGCG
4 seq_noP NA                 

I think it should default (or have the option) to crop the primers if they are found but to keep it if none or only one is found.

PS. I realize the the function is a wrapper for bioseq::seq_crop_pattern where this is the documented behavior...