Fixed CI build failure due to Python setup

[sauwming]

To fix the following error:

Run cd pjsip-apps/src/swig && make
/Applications/Xcode_14.2.app/Contents/Developer/usr/bin/make  --no-print-directory -C python 
swig -I../../../../pjlib/include -I../../../../pjlib-util/include -I../../../../pjmedia/include -I../../../../pjsip/include -I../../../../pjnath/include -c++  -w312 -threads -DSWIG_NO_EXPORT_ITERATOR_METHODS -python -o pjsua2_wrap.cpp ../pjsua2.i
python3 setup.py build 
Traceback (most recent call last):
  File "/Users/runner/work/pjproject/pjproject/pjsip-apps/src/swig/python/setup.py", line 20, in <module>
    from distutils.core import setup, Extension
ModuleNotFoundError: No module named 'distutils'
make[1]: *** [_pjsua2.so] Error 1
make: *** [python] Error 2
Error: Process completed with exit code 2.