Jailbreak specific default repo shouldn’t be removable

[kyondev]

Describe the bug

The jailbreak specific default Repo can be removed. (e.g. Binger/Elucubratus repo for checkra1n)

To Reproduce

Try to remove the default repo

Expected behavior

The option to delete should be missing or not working on that specific repo like for the stable Zebra repo

Screenshots

Device Information:

• iOS Version: 12.4.8
• Zebra Version: 1.2~beta4c
• Device Type: iPhone7,2/iPhone 6
• Jailbreak Type: checkra1n

Crash Log or System Log

Additional context

[wstyres]

This isn't a bug so we'll consider it a feature request.

The reason Zebra doesn't currently have this is because we add no "default repos". We're going to be merging sources.lists soon (#1369) so jailbreaks will be able to provide their own default repos.