Try to filter to only nhmmer valid
Try to filter to only nhmmer valid

This is for RNAcentral/rnacentral-sequence-search#103. We should only
have parsable sequences in the sequence search dataset. This should
select only the sequences that nhmmer can work with.

RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline,RNAcentral/rnacentral-import-pipeline