Add a task to call eth_config and check if there are differences between clients

[parithosh]

network_params:
  network: sepolia

and run the test:

externalTests:
  - file: ./playbooks/fusaka-dev/kurtosis/ethconfig-test-with-rpc-call.yaml

So even on a fresh network, the test is setup to query the API and we can check the configured eth_config and make sure it works on a running network.