✨(all) support a dedicated domain for the PostHog feature flag API

Ad blockers recently started blocking requests to our PostHog
feature flag API, leading to undesired behavior in the app.

Following PostHog's documentation, allow configuring a dedicated
domain for feature flags, isolated from the main PostHog domain.

src/frontend/src/api/useConfig.ts

@@ -9,6 +9,7 @@ export interface ApiConfig {
   analytics?: {
     id: string
     host: string
+    flags_api_host?: string
   }
   support?: {
     id: string

src/frontend/src/features/analytics/hooks/useAnalytics.ts

@@ -28,10 +28,16 @@ export const terminateAnalyticsSession = async () => {
 export type useAnalyticsProps = {
   id?: string
   host?: string
+  flags_api_host?: string
   isDisabled?: boolean
 }
 
-export const useAnalytics = ({ id, host, isDisabled }: useAnalyticsProps) => {
+export const useAnalytics = ({
+  id,
+  host,
+  flags_api_host,
+  isDisabled,
+}: useAnalyticsProps) => {
   const [location] = useLocation()
   const { user } = useUser()
 
@@ -39,9 +45,13 @@ export const useAnalytics = ({ id, host, isDisabled }: useAnalyticsProps) => {
     if (!id || !host || isDisabled) return
     getPosthog().then((ph) => {
       if (ph.__loaded) return
-      ph.init(id, { api_host: host, person_profiles: 'always' })
+      ph.init(id, {
+        api_host: host,
+        flags_api_host: flags_api_host,
+        person_profiles: 'always',
+      })
     })
-  }, [id, host, isDisabled])
+  }, [id, host, flags_api_host, isDisabled])
 
   useEffect(() => {
     if (!user) return