fix gh-139801, make able to pickle BaseProxy

Author: deadlovelll

Lib/multiprocessing/managers.py

@@ -909,9 +909,7 @@ def _after_fork(self):
             util.info('incref failed: %s' % e)
 
     def __reduce__(self):
-        kwds = {}
-        if get_spawning_popen() is not None:
-            kwds['authkey'] = self._authkey
+        kwds = {"authkey": self._authkey}
 
         if getattr(self, '_isauto', False):
             kwds['exposed'] = self._exposed_