consistent query bug

[kjnilsson]

Describe the bug

https://github.com/rabbitmq/ra-kv-store/actions/runs/12121409210

In. one test (in a long history of non failing runs) one leader in a minority partition decided it was ok to serve consistent reads.
After a fair bit of time investigating it wasn't clear exactly what caused it but I suspect it was due to the leader somehow ending up with an incorrectly high query_index for one of it's peers.

The consistent query logic can be refactored to avoid relying on this piece of state entirely as all it does is perform a leader liveness check then waits for the commit index to be appled then execute the query.

This check can be done without each member keeping a query_index and instead just returning the {term, index} tuple provided if the term is equal or higher.

Reproduction steps

https://github.com/rabbitmq/ra-kv-store/actions/runs/12121409210

Expected behavior

.

Additional context

No response