FE events are marked NOT VALID due to unsupported gitlab_experiment context properties

While reviewing my change from this QA issue, I noticed that the events I was tracking were being marked as NOT VALID by Snowplow:

This is due to another change of mine (from another QA issue) which moves the primary source of frontend data for experiments from window.gon.experiment to window.gl.experiments and makes use of a different source of that data from the gitlab-experiment gem – that is, ApplicationExperiment.published_experiments, which includes the new excluded information.