perf(l1): filter empty storages from snapshots

[Oppen]

During snap sync, specifically when downloading storages, we were accidentally dumping all account addresses in every file, even when that file had no storages for most of them.
By filtering, we reduce from 40GiB to 27GiB the auxiliary files in Sepolia, and the sync goes from 3h10' to 3h2' in ethrex-sync-3, and for mainnet in ethrex-sync-2 we got from 185GiB to 40GiB and from 8h6' to 7h7'.

[github-actions]

Lines of code report

Total lines added: 2
Total lines removed: 0
Total lines changed: 2

Detailed view

+----------------------------------------------+-------+------+
| File                                         | Lines | Diff |
+----------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/peer_handler.rs | 1670  | +2   |
+----------------------------------------------+-------+------+

[Copilot]

Pull Request Overview

This PR optimizes L1 network performance by filtering out empty storage entries from snapshots before encoding them. The change reduces the size of encoded snapshots by excluding accounts with no storage data.

• Adds filtering to remove empty storage collections from account snapshots
• Applied consistently across two snapshot creation locations in the peer handler

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[github-actions]

Benchmark Block Execution Results Comparison Against Main

Command	Mean [s]	Min [s]	Max [s]	Relative
base	87.351 ± 0.230	87.054	87.837	1.00 ± 0.00
head	87.242 ± 0.146	87.098	87.546	1.00

[MegaRedHand]

LGTM. Left a small nit

[MegaRedHand]

Nit: this needs more context

Suggested change

	- Avoid dumping empty storage accounts to disk [#4590](https://github.com/lambdaclass/ethrex/pull/4590)
	- Avoid dumping empty storage accounts to disk during snap sync [#4590](https://github.com/lambdaclass/ethrex/pull/4590)

[ilitteri]

+1

[damiramirez]

🚀

[ilitteri]

Removed from the merge queue until it is tested enough.