fix(service): properly wrap luna errors in asyncCall

[kitsuned]

if luna callee returns an error (returnValue is false), asyncCall throws the raw payload object instead of an Error.

further down the call stack, tryRespond catches this value and calls assertNodeError.

assertNodeError checks whether the argument's prototype is Error and throws a new error if a raw payload is passed.

as a result, this leads to an unhandled promise rejection. HBC's Luna service does not send a response to client, which causes request calls to hang indefinitely.

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this PR fixes promise rejection.

[throwaway96]

This sounds extremely familiar... I thought I fixed (something exactly like?) this.