Remove `promo_` implicit feature flags
This is part of #218667 (closed)
This reverts changes introduced by !27412 (merged),
the promo_
feature flag check.
The intent of promo_<licensed_feature>
was to allow enabling feature for everyone
skipping license check. This does introduce a number of implicit licensed feature flags
connected with that.
According to https://gitlab.com/gitlab-com/gl-infra/feature-flag-log/-/issues?scope=all&utf8=%E2%9C%93&state=all&search=promo_
we did not use this promo_
check. To reduce a complexity of amount of feature flags
present in source code we should remove it and consider adding another method if this
deems to be useful.