🗜 Restore zip option for guests + 🐛 fix bugs

The bugs were:
- bad hiding/showing parts when ending/cancelling uploads
- bad behavior when mixing zip and regular uploads
8 jobs for fix-150 in 4 minutes and 4 seconds (queued for 20 seconds)
Status Name Job ID Coverage
  Carton
passed carton #516650

00:00:18

passed podcheck #516649

00:00:18

 
  Carton Bdd
passed carton_mysql #516653

00:00:38

passed carton_postgresql #516652

00:00:39

passed carton_sqlite #516651

00:01:40

 
  Tests
passed mysql #516656

00:01:31

58.4%
passed postgresql #516655

00:01:35

58.1%
passed sqlite #516654

00:01:30

59.3%