chore(l1): improved logs for engine calls

[fedacking]

Motivation

The logs for engine calls forkchoice updated and get payload are useful to know when they are triggered to see the state of the client. They should be in info, and use the structured format.

Description

• Made handle_forkchoice and get_engine log to info.
• Made handle_forkchoice and get_engine log used structured logging format.
• Made debug the "Snap sync in progress" message.
• Added payload_id to the forkchoice block production log.

Progress towards issue #4950

Example Output

2025-10-22T15:03:49.600711Z INFO ethrex_rpc::engine::fork_choice: New fork choice request version="v3" head="0xc10720fe7dcbad99eb46fee520a63ce14bd44a354d86f4ebf76a5e81136278b8" safe="0x7539efbc7961746f1239ed9a003b7003e19b1d9e150db5c0a4194a5241f06d91" finalized="v0xf0a386ad788dc9efebef2dd9b46c677e82efe6bb1bd56023f06cb13babc024d6"

[github-actions]

Lines of code report

Total lines added: 6
Total lines removed: 0
Total lines changed: 6

Detailed view

+----------------------------------------------------+-------+------+
| File                                               | Lines | Diff |
+----------------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/engine/fork_choice.rs | 363   | +3   |
+----------------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/engine/payload.rs     | 694   | +3   |
+----------------------------------------------------+-------+------+