Check for ability to group notifications before view appears

The instance information may not have been available when the initial check happened.

See IOS-363 for root cause to fix later

Mastodon/In Progress New Layout and Datamodel/GroupedNotificationFeedLoader.swift

@@ -53,7 +53,7 @@ final public class GroupedNotificationFeedLoader {
     
     private var isFetching: Bool = false
 
-    private let useGroupedNotificationsApi: Bool
+    public let useGroupedNotificationsApi: Bool
     private let cacheManager: (any NotificationsCacheManager)?
     
     private let user: MastodonUserIdentifier?

Mastodon/In Progress New Layout and Datamodel/NotificationListViewController.swift

@@ -41,6 +41,10 @@ class NotificationListViewController: UIHostingController<NotificationListView>
             "init(coder:) not implemented for NotificationListViewController")
     }
     
+    override func viewWillAppear(_ animated: Bool) {
+        viewModel.checkCanGroupNotifications()
+    }
+    
     @objc private func showNotificationPolicySettings(_ sender: Any) {
         guard let policy = viewModel.filteredNotificationsViewModel.policy else { return }
         Task {
@@ -393,6 +397,16 @@ private class NotificationListViewModel: ObservableObject {
             break
         }
     }
+    
+    func checkCanGroupNotifications() {
+        guard let currentInstance = AuthenticationServiceProvider.shared.currentActiveUser.value?.authentication.instanceConfiguration else {
+            presentError?(APIService.APIError.implicit(.authenticationMissing))
+            return
+        }
+        if currentInstance.canGroupNotifications, !feedLoader.useGroupedNotificationsApi {
+            createNewFeedLoader()
+        }
+    }
 
     private func createNewFeedLoader() {
         fetchFilteredNotificationsPolicy()

MastodonSDK/Sources/MastodonCore/MastodonAuthentication.swift

@@ -44,7 +44,7 @@ public struct MastodonAuthentication: Codable, Hashable, UserIdentifier {
         
         public var canGroupNotifications: Bool {
             switch self {
-            case let .v1(instance):
+            case let .v1(_):
                 return false
             case let .v2(instance, _):
                 guard let apiVersion = instance.apiVersions?["mastodon"] else { return false }