fix: fix re-use string for user-ops sender/to

[ccharly]

We recently narrowed the type used for EthAddressStruct to be Hex. This actually have a huge impact on various types that depend on it.

While most of the account types are fine, the user-ops one also bubbles up to the TransactionController and would require a bit more refactor to re-type everything correctly.

For now, we'll just revert to what it was and keep them as string for those types.

---

Note

Medium Risk
Touches shared Ethereum address validation/types, which can ripple through downstream type inference and RPC param validation; behavior should be mostly compatible but type-level impacts are broad.

Overview
Reverts EthAddressStruct’s inferred type back to string (while keeping the same 0x…{40} validation regex) to undo an unintended breaking change that propagated into ERC-4337/user-op address-like fields.

Introduces EthAddressStrictStruct (Hex-typed) for callers that need strict Hex inference, and updates EIP-7702 authorization tuple validation to use this stricter struct. The changelog documents the revert and notes 21.4.0 will be yanked.

^{Written by Cursor Bugbot for commit 2b1eb24. This will update automatically on new commits. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.