adjust enrollment status telemetry to only send for active experiments

[jeddai]

https://sql.telemetry.mozilla.org/queries/95445/source#235860

^ enrollment_status is sending 15mil/day in Nightly Fenix. It's including all experiment enrollments that exist in the database on-device, which could go back a year.

Pull Request checklist

• Breaking changes: This PR follows our breaking change policy
  • This PR follows the breaking change policy:
    • This PR has no breaking API changes, or
    • There are corresponding PRs for our consumer applications that resolve the breaking changes and have been approved
• Quality: This PR builds and tests run cleanly
  • Note:
    • For changes that need extra cross-platform testing, consider adding [ci full] to the PR title.
    • If this pull request includes a breaking change, consider cutting a new release after merging.
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry in CHANGELOG.md or an explanation of why it does not need one
  • Any breaking changes to Swift or Kotlin binding APIs are noted explicitly
• Dependencies: This PR follows our dependency management guidelines
  • Any new dependencies are accompanied by a summary of the due dilligence applied in selecting them.

Branch builds: add [firefox-android: branch-name] to the PR title.

[rvandermeulen]

@Mergifyio backport release-v120

[mergify]

backport release-v120

✅ Backports have been created

• #5954 adjust enrollment status telemetry to only send for active experiments (backport #5889) has been created for branch release-v120