query-param: fix clang-tidy warnings

```
../redfish-core/include/utils/query_param.hpp:287:51: error: unsafe pointer arithmetic [-Werror,-Wunsafe-buffer-usage]
    auto it = std::from_chars(value.data(), value.data() + value.size(),
                                            ~~~~~~^~~~~~
../redfish-core/include/utils/query_param.hpp:307:45: error: unsafe pointer arithmetic [-Werror,-Wunsafe-buffer-usage]
        std::from_chars(value.data(), value.data() + value.size(), param);
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ic93d3e98e0539f5c7068b93ff7e4505fdd5bbfe1