Change controller validate helper method to behave like Laravel (#1247)

[MattApril]

#1247

[driesvints]

Tests are failing here.

[MattApril]

Whoops, I forgot that I overwrote my own exception handler. Looks like Lumen's default handler excepts the response to be set on the ValidationException. Fixed.

[taylorotwell]

Would this break existing applications?

[MattApril]

Yes, it would cause a breaking change if anyone overwrote the protected extractInputFromRules or throwValidationException methods. I just updated it to use those methods if they are defined.

[halloei]

This broke my application. I'm not overwriting extractInputFromRules() and throwValidationException(), I'm calling them directly from my controller.

[driesvints]

We're reverting this.

[MattApril]

Hmm, that was an unfortunate oversight. Sorry about that.

I think this should be released as a breaking change in the next major version though. The current validation is not behaving as expected.