filter_vep_transcript_csqs does not work for passing list of CSQ terms

[mike-w-wilson]

There is a bug here: https://github.com/broadinstitute/gnomad_methods/blob/019865838f993841a540e0b29d8d2f3b1333b1b8/gnomad/utils/vep.py#L788

The most_severe_consequence field is a top level vep field, at the same level as transcript_consequences, so the way this is currently built does not work as the function looks for most_severe_consequence inside of transcript_consequences here. All other vep fields that get worked on in this function are within transcript_consequences so they work.