Kill operation on node deregistration

[p-ferreira]

Both validators and miners should stop operating whenever the node gets deregistered. The previous text-prompting repo handles that at the validator side, we should ensure this behaviour is enabled by default on the new repo, both for miners and validators

[p-ferreira]

Link to specific if to check node registration in previous repo:
https://github.com/opentensor/text-prompting/blob/b126ac10e78844715df20f94a19e0515fcdd89b9/neurons/validators/validator.py#L105