[Feature] Add `signer` field in `Signed` tx - Use `OnceLock`

[yash-atreya]

Component

consensus, eips, genesis

Describe the feature you would like

Motivation

Ref https://github.com/alloy-rs/alloy/pull/472#discussion_r1556009874

Solution

Add a signed_by: OnceLock<Address> field in Signed tx

Additional context

No response