Optimize cached online user lookups (#6595)

Co-authored-by: JRoy <10731363+JRoy@users.noreply.github.com>

Author: NeglectDream

Essentials/src/main/java/com/earth2me/essentials/userstorage/ModernUserMap.java

@@ -102,6 +102,13 @@ public User getUser(final UUID uuid) {
 
     @Override
     public User getUser(final Player base) {
+        final UUID uuid = base.getUniqueId();
+        final User cachedUser = userCache.getIfPresent(uuid);
+        if (cachedUser != null && cachedUser.getBase() == base) {
+            uuidCache.updateCache(uuid, base.getName());
+            return cachedUser;
+        }
+
         final User user = loadUncachedUser(base);
         userCache.put(user.getUUID(), user);
         debugLogCache(user);