log and handle enclave exrinsic failures

[brenzi]

In our live deployment, we observed one service startup where anclave registration succeeded and sidechain production worked, but no extrinsics were included about confirmParentchainProcesses, or confirmsidechainBlock.

The enclave account has enough balance.
Restarting the service solved the issue
As not even Extrinsic failures were reported, I assume that the nonce was wrong.

The log showed nothing at all (was set to WARN level only)

handling such errors isn't trivial because availability of the sidechain may be more important than finalization on L1

But it sure should be logged with a decent error msg.

If the problem is indeed the nonce, recovery (or even solving the root cause) should be easy to implement