scripts: reduce the k-mer length in launch script

Link: https://github.com/GeneAssembly/biosal/issues/815
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
unitig: visitor reports vertex counts to manager

Link: https://github.com/GeneAssembly/biosal/issues/815
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>