Use growthbook react and use new event for experiments #4068

Summary

Refactor experiments to use growthbook react and the new snowplow event

closes #4068 (closed)

Test instructions

⚠ Use the feat-grothbook-react-qa build to test (Only iOS because it need to point to the staging servers)

• log in with different users
• The active tab indicator border-color changes with a probability of 50% / 50% between Yellow/Blue

Estimated Regression Scope

No regression is expected as there are no experiments at the moment on the app