branch-2.1: [Bug](function)fix json_object function check null nums error as return bool #44321 (#44381)

Cherry-picked from #44321

Co-authored-by: zhangstar333 <zhangsida@selectdb.com>

be/src/vec/functions/function_json.cpp

@@ -784,13 +784,13 @@ public:
         for (int i = 0; i < args; i += 2) {
             const auto* null_map = nullmaps[i];
             if (null_map) {
-                const bool not_null_num =
+                auto not_null_num =
                         simd::count_zero_num((int8_t*)null_map->get_data().data(), size);
                 if (not_null_num < size) {
                     return Status::InternalError(
                             "function {} can not input null value , JSON documents may not contain "
-                            "NULL member names.",
-                            name);
+                            "NULL member names. input size is {}:{}",
+                            name, size, not_null_num);
                 }
             }
         }