BlockSpec check_state_transition

[turuslan]

🗒️ Description

Add check_state_transition to BlockSpec.
Fixes test_process_slots_target_equal_to_state_slot_rejected test.

Can be backported to devnet4.

🔗 Related Issues or PRs

Closes #1183

✅ Checklist

• Ran local quality checks to avoid unnecessary CI fails:

  just check

[leolara]

This fixes it :-)

Not specific about this PR, but in general, my opinion is that the interface should be different, but I can send that in a different Pr after this is merged.

The test writer writes state_transition(pre_state, block), so the interface is hiding that things are being done to the pre_state before calling state_transition by default. I think the default would be to use the pre_state as is, and if we would like to process_slots before calling state_transition, that would be the extra option.

I think that would follow better the principle of Least Surprise.