[EFM] Modify implementors of protocol.DKG to use IndexMap

[durkmurder]

Context

Currently implementors of protocol.DKG rely on the fact that there are equal numbers of keys and consensus committee members, and if $C$ is ordered according to canonical ordering, then $K[i]$ is the key for $C[i]$. Extend current implementation to rely on IndexMap to obtain correct DKG index and respective key share.

Definition of done

• Implementors of protocol.DKG use IndexMap to retrieve correct key share.
• Update generated unit test fixtures.
• Update tests.

For extra details refer to parent issue: #6214