Improve append_extrinsic to return a DispatchResult

[lemunozm]

Currently if an extrinsic fails, it returns a () as error, would be awesome to return a DispatchResult instead (not sure is it feasible)

[lemunozm]

@cdamian is your last fudge adventure did you have a chance to know if this is feasible?

[cdamian]

@lemunozm we're already returning an error now - https://github.com/centrifuge/fudge/blob/master/core/src/builder/core.rs#L645

Not sure if a DispatchResult would be possible though, we have to rely on the error that was returned by the pool when submitting the transaction.

[lemunozm]

Cool! I just see that the error is also returned in the macro expansion. More cool!

[lemunozm]

After searching about this, it seems not possible. Nothing except a string of the error is propagated (https://github.com/paritytech/polkadot-sdk/blob/master/substrate/utils/frame/rpc/system/src/lib.rs#L164). The error could later be read in the event, but you need to evolve the chain at least one block to get it.