[Feature Request] Short-circuit async shard fetch batches to limit reroute execution time

[Bukhtawar]

Is your feature request related to a problem? Please describe

As a part of assigning existing copies of shards we create async shard batches. Since batches run sequentially today, they can very well over-run causing high priority tasks to get timed out.

Describe the solution you'd like

While there are opportunities to optimise the loop further, it'd be good if we can time-bound batch executions. As in skip batch execution for shard assignment once certain time interval has elapsed.

Related component

ShardManagement:Performance

Describe alternatives you've considered

No response

Additional context

No response