[Platform] Additional upgrade checks for cluster health before moving on to next node

[iSignal]

Currently we check the following before completing the upgrade operation on one node and moving to another node.

• Check that the restarted tserver responds to an RPC call
• Check that the restarted tserver heartbeats to the leader master

In the case of smart AMI upgrades and smart instance type changes, we will be keeping nodes down for potentially longer periods of time. This calls for additional checks on the tserver before moving on

• Check that the restarted tserver reclaims its tablets in case it was down for > 15 mins and if its tablets were unassigned as a result.
• Check that the restarted tserver catches up via WAL to its corresponding tablet leaders in case it was down for < 15 mins but has yet to catch up via WAL.
• Potentially another check for masters in case they are kicked out if the cluster.

#8882