[Epic] [Feature Flag] Firebase Support

[bruno-garcia]

Problem Statement

Sentry is working on bringing FF context into its telemetry data:

• https://docs.sentry.io/product/issues/issue-details/feature-flags/

Support for JavaScript and Python for several providers already exist. For example Unleash, LaunchDarkly, and Statsig.

Firebase has a remote config feature: https://firebase.google.com/docs/remote-config
It's popular specially amongst mobile apps in particular.

We'd like to add support for:

• Change Tracking. Track Flag state changes via web hook
• Various SDK support for tracking FF Evaluations
  • Firebase Web SDK support for tracking FF evaluations
  • [EPIC] Mobile Feature Flags team-mobile#206
    • [React Native] Feature Flags Reporting - Firebase Remote Config integration sentry-react-native#4591
    • [Flutter] Feature Flags Reporting - Firebase Remote Config integration sentry-dart#2748
    • [Feature Flag]: Firebase Remote Config support sentry-unity#2043
    • Native iOS support
    • Native Android support