Filter experiment data to match the gitlab_experiment context

What does this MR do and why?

Moves the attribute filter which was set up in !74443 (merged) to a higher, broader level. The previous implementation really only helped with one FE event; this MR’s implementation resolves the NOT VALID Snowplow event issue for all FE experiment events (since they all make use of getExperimentData which uses getExperimentsData under the hood).

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

---

Related to #345622 (closed)