* obs-scripting: Fix unused 'varargs' warning
* obs-scripting: Fix PyEval deprecation warnings
Remove PyEval_InitThreads() and PyEval_ThreadsInitialized() call for
Python 3.7 and later as Python calls it automatically now.
This removes deprecation warnings when using Python 3.9 or later.
https://docs.python.org/3/c-api/init.html#c.PyEval_InitThreads