fix(mobile): fix typos (#16456)

Found via codespell

mobile/lib/services/auth.service.dart

@@ -75,7 +75,7 @@ class AuthService {
         isValid = true;
       }
     } catch (error) {
-      _log.severe("Error validating auxilary endpoint", error);
+      _log.severe("Error validating auxiliary endpoint", error);
     } finally {
       httpclient.close();
     }
@@ -187,7 +187,7 @@ class AuthService {
         _log.severe("Cannot resolve endpoint", error);
         continue;
       } catch (_) {
-        _log.severe("Auxilary server is not valid");
+        _log.severe("Auxiliary server is not valid");
         continue;
       }
     }

mobile/lib/services/background.service.dart

@@ -329,7 +329,7 @@ class BackgroundService {
         try {
           _clearErrorNotifications();
 
-          // iOS should time out after some threshhold so it doesn't wait
+          // iOS should time out after some threshold so it doesn't wait
           // indefinitely and can run later
           // Android is fine to wait here until the lock releases
           final waitForLock = Platform.isIOS

mobile/lib/services/sync.service.dart

@@ -639,7 +639,7 @@ class SyncService {
   }
 
   /// fast path for common case: only new assets were added to device album
-  /// returns `true` if successfull, else `false`
+  /// returns `true` if successful, else `false`
   Future<bool> _syncDeviceAlbumFast(Album deviceAlbum, Album dbAlbum) async {
     if (!deviceAlbum.modifiedAt.isAfter(dbAlbum.modifiedAt)) {
       return false;