[GSI][Upgrade] Failed over and rebalanced out pre-spock indexer node cannot be added back to spock cluster after upgrade

Steps:

1. Create a pre-spock cluster with above mentioned configuration. Initial Version: 4.6.0-3573
2. Upgrade Node 1 to spock. Version: 5.0.0-2958
3. Fail over Node 2.
4. Upgrade Node 3 to Spock.
5. Rebalance out Node 2.
6. Upgrade Node 2.
7. Try to add Node 2 back to the cluster.

Following error is observed:

Attention: This node cannot add another node ('ns_1@10.111.180.102') because of cluster version compatibility mismatch. Cluster works in [5, 0] mode and node only supports [4, 6]

Screenshot, Logs attached