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/lighthouse_network/src/service/mod.rs

@@ -282,7 +282,7 @@ impl<E: EthSpec> Network<E> {
 
             let max_topics = ctx.chain_spec.attestation_subnet_count as usize
                 + SYNC_COMMITTEE_SUBNET_COUNT as usize
-                + ctx.chain_spec.blob_sidecar_subnet_count_electra as usize
+                + ctx.chain_spec.blob_sidecar_subnet_count_max() as usize
                 + ctx.chain_spec.data_column_sidecar_subnet_count as usize
                 + BASE_CORE_TOPICS.len()
                 + ALTAIR_CORE_TOPICS.len()