drop unalignable example sequences

[j23414]

Description of proposed changes

In response to threads here and here, drop the unknown >GenBank_? example sequences.

smof grep -v "?" sequences.fasta > temp.fasta
mv temp.fasta sequences.fasta
# check headers
grep ">" sequences.fasta | less

Related issue(s)

Checklist

• [x] Checks pass

[j23414]

merging as this change is already reflected in the dengue/all dataset