Remove peer sampling code (#7768)

Peer sampling has been completely removed from the spec. This PR removes our partial implementation from the codebase.
https://github.com/ethereum/consensus-specs/pull/4393

beacon_node/beacon_chain/src/chain_config.rs

@@ -96,8 +96,6 @@ pub struct ChainConfig {
     pub enable_light_client_server: bool,
     /// The number of data columns to withhold / exclude from publishing when proposing a block.
     pub malicious_withhold_count: usize,
-    /// Enable peer sampling on blocks.
-    pub enable_sampling: bool,
     /// Number of batches that the node splits blobs or data columns into during publication.
     /// This doesn't apply if the node is the block proposer. For PeerDAS only.
     pub blob_publication_batches: usize,
@@ -148,7 +146,6 @@ impl Default for ChainConfig {
             epochs_per_migration: crate::migrate::DEFAULT_EPOCHS_PER_MIGRATION,
             enable_light_client_server: true,
             malicious_withhold_count: 0,
-            enable_sampling: false,
             blob_publication_batches: 4,
             blob_publication_batch_interval: Duration::from_millis(300),
             sync_tolerance_epochs: DEFAULT_SYNC_TOLERANCE_EPOCHS,