Update to cosmos v0.38.4 and one revert hack

[NicolasMahe]

• [x] update to cosmos https://github.com/cosmos/cosmos-sdk/releases/tag/v0.38.4
• [x] revert hack on the decorator: https://github.com/mesg-foundation/engine/blob/70eaa421555415022aba4a1d80a1a1521cb09179/app/app.go#L316-L337