The grants part wrote its own wrapper into mesh-grants_memberships while the tool runner read the value as a bare
membership: novox's tool runner served no tool. EncodeGrantsMembership writes the bare membership;
DecodeGrantsMembership and BareGrantsMembership read it, still read the old wrapper for the transition, and refuse a
value naming no node or module instead of answering an empty membership.
Issue 774 (the bus login list, L3). Quick fix: write the bare membership in the grants part alone. Thorough, chosen:
one codec in mesh-sdk both sides use, because a hand-built test fixture agreed with the mistake and hid it.