Fix crash in profile due to accessing data source before it exists

This could happen if an account is updated in the background while a
profile is on screen and the user has not visited all of the tabs.

Tusker/Screens/Profile/ProfileStatusesViewController.swift

@@ -41,16 +41,6 @@ class ProfileStatusesViewController: UIViewController, TimelineLikeCollectionVie
         
         self.controller = TimelineLikeController(delegate: self)
         
-        mastodonController.persistentContainer.accountSubject
-            .receive(on: DispatchQueue.main)
-            .filter { [unowned self] in $0 == self.accountID }
-            .sink { [unowned self] id in
-                var snapshot = dataSource.snapshot()
-                snapshot.reconfigureItems([.header(id)])
-                dataSource.apply(snapshot, animatingDifferences: true)
-            }
-            .store(in: &cancellables)
-        
         addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: "Refresh Profile"))
     }
     
@@ -98,6 +88,15 @@ class ProfileStatusesViewController: UIViewController, TimelineLikeCollectionVie
     override func viewDidLoad() {
         super.viewDidLoad()
                 
+        mastodonController.persistentContainer.accountSubject
+            .receive(on: DispatchQueue.main)
+            .filter { [unowned self] in $0 == self.accountID }
+            .sink { [unowned self] id in
+                var snapshot = dataSource.snapshot()
+                snapshot.reconfigureItems([.header(id)])
+                dataSource.apply(snapshot, animatingDifferences: true)
+            }
+            .store(in: &cancellables)
     }
     
     private func createDataSource() -> UICollectionViewDiffableDataSource<Section, Item> {