Verify configurable exception classes in setter method

[viralpraxis]

I doubt anyone will intentionally set argument_error_class/failure_class to some non-exception objects, but it's possible due to dummy mistake or misunderstanding. The problem here is that it wont be noticed until we try to raise something unraisable in actor failure scenario

So I think we can be a little be more defensive here

@sunny I'll add a changelog entry if you approve the idea

[sunny]

Awesome! It makes much sense, I’m all for being more defensive 👏🏻

[viralpraxis]

Awesome! It makes much sense, I’m all for being more defensive 👏🏻

Updated changelog 👍🏻

[sunny]

👏🏻