Include Raft term information in etcd-member lease for more informartion

[ishan16696]

How to categorize this issue?
/area disaster-recovery
/kind enhancement

What would you like to be added:

Currently, etcd-member lease only contains information <MemberID>:<MemberRole> which can be misleading example in this case as etcd-main-2 and etcd-main-1 both are shown as leader but actually etcd-main-2 which was previous leader is down, so it's backup-restore unable to update it's lease, hence it's contain stale information.

etcd-main-0                  8e9e05c52164694d:Member                                                           376d
etcd-main-1                  c0155982ce9f6541:Leader                                                           376d
etcd-main-2                  76d3bd25db9ab8eb:Leader                                                           376d

To avoid that If we would have RAFT-term mentioned then it will be very easy to detect that who is new leader and who was a leader in previous RAFT term.
With this PR: #913, lease will now also contains the clusterID but I still feel they should also contain RAFT-term as well.

Why is this needed:

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