[ENSCORESW-224]. Fix for multi-line SQ lines caused by large sequences being...

[ENSCORESW-224]. Fix for multi-line SQ lines caused by large sequences being pushed through SeqDumper. Was never an issue before as our slices were never big enough. Applied the same fix to Genbank but it should be less of an issue due to it's formatting meaning we need larger slices to cause the issue.