Avoid reading wasm code for non-wasm governance proposal

[grarco]

https://github.com/anoma/namada/blob/621cce94399e3ce5088e07dfff842f438b216103/crates/apps/src/lib/node/ledger/shell/governance.rs#L122

Here it looks like we read the proposal code from storage even though we know that the transaction doesn’t have on. Also, we ignore the actual result of the proposal and always log that it was successful