For the nf-core/rnaseq wrapper, when the Advanced "UMI" option is selected (to pass --with-umis), we should do a sanity check on the user provided FASTQs to ensure they actually have UMIs in the header and fail fast if they don"t.

Otherwise, the pipeline runs until it fails on umitools with an error about unequal UMI lengths, eg "AssertionError: not all umis are the same length(!): 4 - 5".

We could go further, and make a "Use UMIs" dropdown option "auto" by default - checking if UMIs are present and throwing the --with-umis option, unless "Use UMIs" is "no".