Forbid unnamed derivation paths for snaps in stable

[rekmarks]

Snaps can request arbitrary derivation paths via their key management permissions. We have human-readable names for some derivation paths via @metamask/slip44, but since there are infinite derivation paths, we are going to lack names for most of them. If we don't have a legible name for a derivation path, the user cannot understand the authority granted by the permission, and the permission is unsuitable for production.

Unnamed derivation paths should be rejected in stable, but remain permitted in Flask.

[hmalik88]

So in essence, we are rejecting anything non slip-44 for stable? We don't have any resolution service for non slip-44.

[hjetpoluru]

This is a low-priority enhancement that was discussed with the Snaps team during refinement.