[3.13] gh-150484: Fix mock_open __exit__ with contextlib.ExitStack (GH-151829) (GH...

[3.13] gh-150484: Fix mock_open __exit__ with contextlib.ExitStack (GH-151829) (GH-151861)

  mock_open's _exit_side_effect had a fixed 3-arg signature, but
  contextlib.ExitStack calls __exit__ with 4 args (self + 3 exc info).
  Use *args to accept any number of arguments.
(cherry picked from commit 85fa295073a0291e517ae6bd24a26e03b5925b75)

Co-authored-by: Zang Peiyu <166481866+factnn@users.noreply.github.com>