Insert captcha widget even if placement is NULL

Thanks @jurgenhaas - how sure are we, that this doesn't introduce any unwanted side-effects? Generally I'd be fine with this change, but I'm not really sure about possible edge-cases, especially in existing installations.

how sure are we, that this doesn't introduce any unwanted side-effects?

I'm pretty certain. Here is why:

• The method $captchaService->insertCaptchaElement is explicitly built to allow for a NULL placement. That must have been done on purpose.
• The NULL value for placements can only happen on forms without buttons. But the assumption that forms without buttons shouldn't get a captcha is not reasonable.

So, what's the risk that I'm wrong? Well, if there is an unintended side-effect, it could only be on forms with no buttons. Do they exist and why? I think, chances are negligible.

Thanks for your feedback @jurgenhaas. I agree the risks are low enough, the benefit is much higher. Let's merge this.