feat(rln): get more specific error details using viem types

[adklempner]

Description

Currently, we naively log the error thrown by viem when interacting with wallet/blockchain.

Viem provides specific error types that can be used to produce more granular error messages/logic:
https://viem.sh/docs/contract/simulateContract#handling-custom-errors
https://viem.sh/docs/error-handling#error-handling

User Story

Proposed Solution / Feature Design

Optional: Diagram or Draft of Design

Notes