Fork aware max values in rpc (#6847)

N/A


  In https://github.com/sigp/lighthouse/pull/6329 we changed `max_blobs_per_block` from a preset to a config value.
We weren't using the right value based on fork in that PR. This is a follow up PR to use the fork dependent values.

In the proces, I also updated other places where we weren't using fork dependent values from the ChainSpec.

Note to reviewer: easier to go through by commit

beacon_node/network/src/service.rs

@@ -312,6 +312,7 @@ impl<T: BeaconChainTypes> NetworkService<T> {
             invalid_block_storage,
             beacon_processor_send,
             beacon_processor_reprocess_tx,
+            fork_context.clone(),
             network_log.clone(),
         )?;