Wrap errors correctly so that users get readable transaction failures

[jkilpatr]

https://github.com/althea-net/cosmos-gravity-bridge/pull/323/files

The content of this pr is an example of an error type that would not be returned correctly to the user. In the before case the user would see an 'unknown internal error' in the response for their transaction if they hit this error case.

If the error is wrapped properly the user will see the error message in the 'raw_log' section of the tx response, greatly easing debugging.

There are many instances in the codebase of this mistake, and the above example pr only corrects one of them. This ticket is for the rest.