Closing last tab causes all groups to be empty

[Joseph-DiGiovanni]

Closing the last tab of the current group closes Firefox and all groups are empty upon reopening.

To Reproduce

1. Open Firefox
2. Close all tabs in active group
3. Firefox closes
4. Reopen Firefox
5. All groups are now empty

Expected behavior
Other groups should remain untouched

Desktop (please complete the following information):

• OS and version: NixOS 24.11
• Firefox version: 135
• Simple Tab Groups version: 5.2

Possibly related to #716 and #1217 but they do not have clear steps to reproduce the issue.