[Feature] 8886 custom fields access too restricted

[``* `#8886`Custom field access too restricted``](https://www.openproject.org/work_packages/8886)
I might be contradicting myself here but I guess that Anonymous should be granted access as long as the require_login setting doesn't prevent it (should already be enforced in a different before_filter. 

The reason I am changing my mind here are the public projects which are OK for Anonymous to see.

So I guess this before filter here can be removed.