Allow throwing an error inside route handler when continueOnError is true

[mdpx]

Hi!
came from #97 , created a sandbox that reproduces the problem -> sandbox.
note the difference between sending a request with correct type but invalid body and a request with wrong type.

it happens when you use a centralized error handling middleware and you throw a proper error in route handlers when ctx.invalid is set.

I think it should be supported and work like a charm so I did some brain work and came up with a solution, will open a pr for this.