cli: improve error when attempting to invoke a non-existing contract

[tomerweller]

I accidentally tried to invoke a contract using the wasm hash as the id (yes, I'm an idiot). The cryptic response was: error: Missing result in successful response. Can we put something more helpful?

Bonus points: Could we add a hint to the error in case the id looks like a wasm hash. "are you trying to use the wasm hash as a contract id"?