message: fix: avoid adding an empty range
  And while we are here, why don't we also check if the range is not empty before pushing it
diff: @@ -69,9 +69,11 @@ namespace Nextclade {
  if (!privateDeletionsSorted.empty() && begin) {
  const auto end = privateDeletionsSorted.back().pos;
  const auto length = end - *begin;
  + if (length > 0) {
  deletionRanges.emplace_back(
  NucleotideRange{.begin = *begin, .end = end, .length = length, .character = Nucleotide::GAP});
  }
  + }
  return deletionRanges;
  }
  