Refactor runTx to include PostHandler cases

[Vvaradinov]

Summary

This is a follow up of #13942. To include the 3 cases for PostHandler in runTx.

Problem Definition

In order to fully support stateful precompiled contracts on Evmos (and other EVM chains using Ethermint), we need to migrate the leftover gas refund logic to the PostHandler. After the runMsg success bool was included - #13940 and additional change to runTx is required to cover the 3 cases for the PostHandler

1. When the tx errors and the PostHandler is not set.
2. When the tx errors and the PostHandler is set
3. When the tx is successful and the PostHandler is set.

Proposal

1. The PostHandler is not set and the tx errors so return the err
2. The tx errors and the PostHandler is set so run the Posthandler with runMsgCtx so that the state from runMsgs is persisted.
3. The tx is successful and the PostHandler is set so run the Posthandler with runMsgCtx so that the state from runMsgs is persisted.

[Vvaradinov]

Closing this since we were able to solve this in another way.