DEBUG initialisation missing for fixed point

Basic info

• Encoder (fix) : e1432023

Bug description

An initialisation is missing in debug, making it impossible to force the stereo mode to FD or TD

#ifdef DEBUGGING
    ( *phIvasEnc )->cmd_stereo = false;
#endif

should be added to IVAS_ENC_Open_fx() (currently that has been added to IVAS_ENC_Open() which is not used during fixed point encoder initialisation.

@malenovsky, I'm not sure if there is already a MR where it could be added.

Ways to reproduce

(Clear steps or refer to a failing automated test, e.g. with a pipeline link)