[core] Remove declaration srt_logger_config again
[core] Remove declaration srt_logger_config again

udt.h is included by app.cpp, which has the declaration of
srt_logger_config.

Haivision/srt,ethouris/srt,ethouris/srt,Cinegy/srt,Haivision/srt,Haivision/srt,ethouris/srt,Cinegy/srt,Cinegy/srt,Haivision/srt,ethouris/srt,Cinegy/srt