Move responsibility for instance configuration updates to the AuthenticationServiceProvider

Fixes IOS-401

MastodonSDK/Sources/MastodonCore/AuthenticationServiceProvider.swift

@@ -39,6 +39,15 @@ public class AuthenticationServiceProvider: ObservableObject {
             .store(in: &disposeBag)
 
         // TODO: verify credentials for active authentication
+        currentActiveUser
+            .throttle(for: 3, scheduler: DispatchQueue.main, latest: true)
+            .sink { authBox in
+                guard let domain = authBox?.domain else { return }
+                Task {
+                    await InstanceService.shared.updateInstance(domain: domain)
+                }
+            }
+            .store(in: &disposeBag)
         
         Task {
             if authenticationMigrationRequired {

MastodonSDK/Sources/MastodonCore/Service/InstanceService.swift

@@ -16,22 +16,6 @@ public final class InstanceService {
     
     static let shared = InstanceService()
     
-    var disposeBag = Set<AnyCancellable>()
-    
-    // output
-
-    init() {
-        AuthenticationServiceProvider.shared.currentActiveUser
-            .receive(on: DispatchQueue.main)
-            .asyncMap { [weak self] in
-                if let domain = $0?.domain {
-                    await self?.updateInstance(domain: domain)
-                }
-            }
-            .sink {}
-            .store(in: &disposeBag)
-    }
-    
 }
 
 extension InstanceService {