chore: Made failed generators only get added on self proposers

[ChaoticTempest]

This cleanups the signature handling we have in the crypto loop to be inside the SignatureManager since that function was getting hairy. Also, we did not need to have failed generators be added every single time to be handled, so we only need to directly keep around the failed ones that we originally introduced into the system.

Also created https://github.com/near/mpc-recovery/issues/596 for our future handling of priority of sign requests

[github-actions[bot]]

Terraform Feature Environment Destroy (dev-597)

Terraform Initialization ⚙️success

Terraform Destroy success

Show Destroy Plan

``` No changes. No objects need to be destroyed. Either you have not created any objects yet or the existing objects were already deleted outside of Terraform. Destroy complete! Resources: 0 destroyed. ```

Pusher: @ChaoticTempest, Action: pull_request, Working Directory: `, Workflow:Terraform Feature Env (Destroy)`