Reg->5.15.1: Exception on subseqent import following QtCore import when used from embedded Python

In the file shibokenmodule/files.dir/shibokensupport/__feature__.py  line 107 reads:

    importing_module = sys._getframe(1).f_globals.get("__name__", "__main__")

When using embedded Python, this may result in ValueError: call stack is not deep enough and crash. I suggest replacing it with:

try:
    importing_module = sys._getframe(1).f_globals.get("__name__", "__main__")
except ValueError:
    importing_module = "__main__"

With this change PySide2 can again work in embedded Python.