remove totalDifficulty from blockResult

[macfarla]

totalDifficulty field was removed from block result in ethereum/execution-apis#570 and PR to remove from example output here

naive implementation that just removes totalDifficulty from blockResult - #8430

PoW is being removed so can be ignored.
But do we need to still include totalDifficulty in the BlockResult obj for clique blocks?

[github-actions]

This issue is stale because it has been open for 6 months with no activity.