Remove Unnecessary Moniker Requirement and Enforce Username Setup for Councilors

[kmlbgn]

Description

The current system logic mandates that councilors provide a unique moniker, even though not all councilors are validators. If a moniker is not provided when claiming the councilor seat, a default moniker is set. Since both the moniker and username must be unique, this logic is flawed. You can review the relevant code here:

sekai/x/gov/keeper/msg_server.go

Lines 733 to 746 in 1b8573d

	identityInfo := []types.IdentityInfoEntry{}
	if msg.Moniker != "" {
	identityInfo = append(identityInfo, types.IdentityInfoEntry{
	Key: "moniker",
	Info: msg.Moniker,
	})
	}
	if msg.Username != "" {
	identityInfo = append(identityInfo, types.IdentityInfoEntry{
	Key: "username",
	Info: msg.Username,
	})
	}

Additionally, once a councilor seat is claimed, the user cannot change the username or moniker. This further compounds the issue with the existing logic. The relevant code can be found here:

sekai/x/gov/keeper/identity_registrar.go

Lines 192 to 204 in 1b8573d

	_, found := k.GetCouncilor(ctx, address)
	if found {
	monikerRecordId := k.GetIdentityRecordIdByAddressKey(ctx, address, "moniker")
	usernameRecordId := k.GetIdentityRecordIdByAddressKey(ctx, address, "username")
	moniker := k.GetIdentityRecordById(ctx, monikerRecordId)
	username := k.GetIdentityRecordById(ctx, usernameRecordId)
	if infos[i].Key == "moniker" && moniker != nil && infos[i].Info != moniker.Value {
	return types.ErrCouncilorMonikerNotAllowedToBeChanged
	}
	if infos[i].Key == "username" && username != nil && infos[i].Info != username.Value {
	return types.ErrCouncilorUsernameNotAllowedToBeChanged
	}
	}

Expected Behavior

1. Remove the moniker requirement for councilors since the moniker is only related to validator activity and not governance.
2. No default value should be set for username if not provided. Claiming a seat without a username should fail; Councilors must set up their username prior to claiming a seat, it's their responsibility.