Recording list shows inexistant `unknown` records and hides what should be there instead

[teh-cmc]

Starting state:

Then one ./examples/python/clock/main.py --steps 1000 --connect later:

Then a second one:

Then a third..:

Then sending a bunch of them one after the other:

---

Starting again from scratch and this time sending a bunch in parallel (./examples/python/clock/main.py --steps 1000 --connect &):

[emilk]

Related:

• Show all loaded recordings as tabs #1905