message: fix SequenceWrapper type determination
  failed in case of Partitioned chains
diff: @@ -67,14 +67,16 @@ function getSequenceWrapper(state: SequenceViewState, structureSelection: Struct
  if (entitySeq && entitySeq.sequence.length <= MaxDisplaySequenceLength) {
  sw = new PolymerSequenceWrapper(data)
  } else {
  - if (Unit.isAtomic(unit) || unit.polymerElements.length > MaxDisplaySequenceLength) {
  + const polymerElementCount = units.reduce((a, v) => a + v.polymerElements.length, 0)
  + if (Unit.isAtomic(unit) || polymerElementCount > MaxDisplaySequenceLength) {
  sw = new ChainSequenceWrapper(data)
  } else {
  sw = new ElementSequenceWrapper(data)
  }
  }
  } else if (Unit.isAtomic(unit)) {
  - if (unit.residueCount > MaxDisplaySequenceLength) {
  + const residueCount = units.reduce((a, v) => a + (v as Unit.Atomic).residueCount, 0)
  + if (residueCount > MaxDisplaySequenceLength) {
  sw = new ChainSequenceWrapper(data)
  } else {
  sw = new HeteroSequenceWrapper(data)
  