message: refactor: remove precondition check
  This check was unnecessarily strict, as PR made the code robust to the incoming non-multiple-of-3 sequences
diff: @@ -61,8 +61,6 @@ void protectCodonInPlace(SpanIterator it) {
  }
  void stripGeneInPlace(NucleotideSequence& seq) {
  - precondition_divisible_by(seq.size(), 3);
  -
  const auto& length = safe_cast<int>(seq.size());
  const auto end = length - (length % 3);
  NucleotideSequenceSpan seqSpan = seq;
  