refactor(optimism/rpc): Use alloy RpcClient in SequencerClient (#15346)

Cargo.lock

@@ -9119,10 +9119,14 @@ version = "1.3.4"
 dependencies = [
  "alloy-consensus",
  "alloy-eips",
+ "alloy-json-rpc",
  "alloy-primitives",
+ "alloy-rpc-client",
  "alloy-rpc-types-debug",
  "alloy-rpc-types-engine",
  "alloy-rpc-types-eth",
+ "alloy-transport",
+ "alloy-transport-http",
  "async-trait",
  "derive_more 2.0.1",
  "jsonrpsee",
@@ -9159,7 +9163,6 @@ dependencies = [
  "reth-tasks",
  "reth-transaction-pool",
  "revm",
- "serde_json",
  "thiserror 2.0.12",
  "tokio",
  "tracing",