Minor performance optimization

dao/src/main/java/org/thingsboard/server/dao/util/KvUtils.java

@@ -51,6 +51,10 @@ public class KvUtils {
             throw new DataValidationException("Key can't be null");
         }
 
+        if (key.length() > 255) {
+            throw new DataValidationException("Validation error: key length must be equal or less than 255");
+        }
+
         if (validatedKeys.getIfPresent(key) != null) {
             return;
         }
@@ -58,9 +62,6 @@ public class KvUtils {
         if (!NoXssValidator.isValid(key)) {
             throw new DataValidationException("Validation error: key is malformed");
         }
-        if (key.length() > 255) {
-            throw new DataValidationException("Validation error: key length must be equal or less than 255");
-        }
 
         validatedKeys.put(key, Boolean.TRUE);
     }