Remove dead code `AnalyticsService.onSignOut`.

DefaultAnalyticsService is observing the Session.

services/analytics/api/src/main/kotlin/io/element/android/services/analytics/api/AnalyticsService.kt

@@ -57,11 +57,6 @@ interface AnalyticsService : AnalyticsTracker, ErrorTracker {
      */
     suspend fun setAnalyticsId(analyticsId: String)
 
-    /**
-     * To be called when a session is destroyed.
-     */
-    suspend fun onSignOut()
-
     /**
      * Reset the analytics service (will ask for user consent again).
      */

services/analytics/impl/src/main/kotlin/io/element/android/services/analytics/impl/DefaultAnalyticsService.kt

@@ -91,11 +91,6 @@ class DefaultAnalyticsService @Inject constructor(
         analyticsStore.setAnalyticsId(analyticsId)
     }
 
-    override suspend fun onSignOut() {
-        // stop all providers
-        analyticsProviders.onEach { it.stop() }
-    }
-
     override suspend fun onSessionCreated(userId: String) {
         // Nothing to do
     }

services/analytics/noop/src/main/kotlin/io/element/android/services/analytics/noop/NoopAnalyticsService.kt

@@ -38,7 +38,6 @@ class NoopAnalyticsService @Inject constructor() : AnalyticsService {
     override suspend fun setDidAskUserConsent() = Unit
     override fun getAnalyticsId(): Flow<String> = flowOf("")
     override suspend fun setAnalyticsId(analyticsId: String) = Unit
-    override suspend fun onSignOut() = Unit
     override suspend fun reset() = Unit
     override fun capture(event: VectorAnalyticsEvent) = Unit
     override fun screen(screen: VectorAnalyticsScreen) = Unit