Use more appropriate names for forkchoice subscriptions

[mattsse]

Describe the feature

this should be named subscribe_safe_block

reth/crates/chain-state/src/notifications.rs

Lines 153 to 157 in 170a396

	/// Convenience method to get a stream of the new safe blocks of the chain.
	fn fork_choice_stream(&self) -> ForkChoiceStream {
	ForkChoiceStream { st: WatchStream::new(self.subscribe_to_safe_block().0) }
	}

we also want a function for finalized

Additional context

No response