Add CI to test finalization against minimal LeanSpec Python client

[shariqnaiyer]

Describe the feature

As the minimal client in LeanSpec by Thomas is becoming more mature. It is reasonable to assume that this client will be matching the spec for every devnet.

Although we have spec tests I think a quick test running Ream against the minimal client and testing for finality will lead to us discovering differences from the spec effectively and quickly.

Additional context

No response