message: Fix crash when undoing a tileset delete.
diff: @@ -1152,12 +1152,17 @@ void ACesium3DTileset::Tick(float DeltaTime) {
  return;
  }
  - updateTilesetOptionsFromProperties();
  -
  if (_tilesetIsDirty) {
  LoadTileset();
  }
  + // If we still don't have a tileset, we're done.
  + if (!this->_pTileset) {
  + return;
  + }
  +
  + updateTilesetOptionsFromProperties();
  +
  std::optional<UnrealCameraParameters> camera = this->GetCamera();
  if (!camera) {
  return;
  @@ -1220,7 +1225,9 @@ void ACesium3DTileset::PostEditChangeProperty(
  const FName PropName = (PropertyChangedEvent.Property)
  ? PropertyChangedEvent.Property->GetFName()
  : NAME_None;
  - if (PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, TilesetSource) ||
  +
  + if (this->_pTileset == nullptr ||
  + PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, TilesetSource) ||
  PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, Url) ||
  PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, IonAssetID) ||
  PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, IonAccessToken) ||
  