Merge sudo_module_register_loghandler and sudo_module_set_default_loghandler.

We now create the LogHandler class for each interpreter in
python_plugin_init() instead of just once in sudo_module_init().
This fixes the crash seen in Py_EndInterpreter() with Python 3.12
and significantly reduces the number of leaked objects tracked by
MemorySanitizer.

plugins/python/sudo_python_module.c

@@ -595,9 +595,6 @@ sudo_module_init(void)
     if (sudo_module_register_baseplugin(py_module) != SUDO_RC_OK)
         goto cleanup;
 
-    if (sudo_module_register_loghandler(py_module) != SUDO_RC_OK)
-        goto cleanup;
-
 cleanup:
     if (PyErr_Occurred()) {
         Py_CLEAR(py_module);