Add missing fstream include

[aaronplusone]

This file makes use of std::ofstream, but does not include the fstream header.

Inclusion avoids the following error:

/ws/src/orbbec/OrbbecSDK/src/ob_camera_node.cpp:1654:25: error: variable ‘std::ofstream ofs’ has initializer but incomplete type
 1654 |       std::ofstream ofs(filename, std::ios::out | std::ios::binary);