FeatureFlagUtil.isPresentAndEnabled does not take shouldBeFCVGated into account, whereas the FeatureFlag::isEnabled C++ function does. We should make sure the javascript feature flag helper functions handle `shouldBeFCVGated` properly

We should look into pulling the C++ `isEnabled` function into the shell functions so that we can use it in the JS tests instead of trying to re-do what's done in C++