unnecessary fastani check

[wwood]

pub fn generate_galah_clusterer<'a>(
    genome_fasta_paths: &'a Vec<String>,
    clap_matches: &clap::ArgMatches,
    argument_definition: &GalahClustererCommandDefinition,
) -> std::result::Result<GalahClusterer<'a>, String> {
    crate::external_command_checker::check_for_fastani();

check should be in init of the clusterer instead