make scheduled methoded protected, fix connection

backend/src/main/java/com/alttd/altitudeweb/controllers/login/LoginController.java

@@ -50,7 +50,7 @@ public class LoginController implements LoginApi {
     private static final ConcurrentMap<String, CacheEntry> cache = new ConcurrentHashMap<>();
 
     @Scheduled(fixedRate = 300000) // 5 minutes in milliseconds
-    private void clearExpiredCacheEntries() {
+    protected void clearExpiredCacheEntries() {
         Instant now = Instant.now();
         int initialCacheSize = cache.size();
         cache.entrySet().removeIf(entry -> entry.getValue().expiry().isBefore(now));