optimize ClassConstantAccessor

string concat is about 10x faster than sprintf, so use it here since it's called many times

src/SDK/Common/Util/ClassConstantAccessor.php

@@ -30,6 +30,6 @@ public static function getValue(string $className, string $constantName)
 
     private static function getFullName(string $className, string $constantName): string
     {
-        return sprintf('%s::%s', $className, $constantName);
+        return $className . '::' . $constantName;
     }
 }