Disable reCAPTCHA for detected spam in issues and merge requests

Problem to solve

Using reCAPTCHA in issues and merge requests to override changes that have been detected as spam has some usability (and additionally licensing) issues. Prior discussion happened in https://gitlab.com/gitlab-org/gitlab-ce/issues/45684.

Additionally forcing our users to proof that they didn't submit spam does not align well with our value to assume positive intent.

Proposal

Introduce a new feature flag that allows to

• have Akismet enabled for monitoring purposes
• have reCAPTCHA disabled (and instead accept every change)

What does success look like, and how can we measure that?

It is possible to disable reCAPTCHA for part of gitlab.com so we can verify if removing it completely is an option.