Deprecate exchangeTransitionConfiguration functionality (#4517)

## Issue Addressed

Solves #4442 
## Proposed Changes

EL clients log errors if we don't query this endpoint, but they are making releases that remove this error logging. After those are out we can stop calling it, after which point EL teams will remove the endpoint entirely. 
Refer https://hackmd.io/@n0ble/deprecate-exchgTC

beacon_node/client/src/builder.rs

@@ -850,9 +850,6 @@ where
                     execution_layer.spawn_clean_proposer_caches_routine::<TSlotClock>(
                         beacon_chain.slot_clock.clone(),
                     );
-
-                    // Spawns a routine that polls the `exchange_transition_configuration` endpoint.
-                    execution_layer.spawn_transition_configuration_poll(beacon_chain.spec.clone());
                 }
 
                 // Spawn a service to publish BLS to execution changes at the Capella fork.

beacon_node/client/src/notifier.rs

@@ -404,14 +404,6 @@ async fn merge_readiness_logging<T: BeaconChainTypes>(
                 "config" => ?other
             ),
         },
-        readiness @ MergeReadiness::ExchangeTransitionConfigurationFailed { error: _ } => {
-            error!(
-                log,
-                "Not ready for merge";
-                "info" => %readiness,
-                "hint" => "try updating Lighthouse and/or the execution layer",
-            )
-        }
         readiness @ MergeReadiness::NotSynced => warn!(
             log,
             "Not ready for merge";