Expose viem public client actions from ViemWalletProvider

### 🚀 The feature, motivation and pitch

It would be helpful to have access to things like [simulateContract](https://viem.sh/docs/contract/simulateContract) from `walletProvider` in custom actions. In the context of a custom action that submits a transaction, being able to simulate the outcome first would allow the LLM to see the contract revert message rather than just seeing if a transaction failed or succeeded.

Or perhaps an easier solution is exposing both public and wallet clients from the wallet provider.