Remove test_logger feature (#9125)

- #9107


  Remove all instances of `test_logger` in the code


Co-Authored-By: Tan Chee Keong <tanck@sigmaprime.io>

beacon_node/network/Cargo.toml

@@ -10,7 +10,6 @@ disable-backfill = []
 fork_from_env = ["beacon_chain/fork_from_env"]
 fake_crypto = ["bls/fake_crypto", "kzg/fake_crypto"]
 portable = ["beacon_chain/portable"]
-test_logger = []
 
 [dependencies]
 alloy-primitives = { workspace = true }