vocab : correct bounds check for UGM XCDA array access (#17215)

src/llama-vocab.cpp

@@ -1013,7 +1013,7 @@ private:
         }
     private:
         uint32_t get_node(size_t index) {
-            if (index > xcda_array_size) {
+            if (index >= xcda_array_size) {
                 throw std::runtime_error("Index out of array bounds in XCDA array!");
             }
             return xcda_array[index];