Follow-up to #47420 and #44193.

#47420 fixed child-exit status handling via upstream alacritty change (alacritty/alacritty#8825). However, stable/preview/nightly builds still reproduced hangs that dev builds did not.

The root cause matches #44193: spawned children inherit crash-handler Mach exception ports and hang. We already reset exception ports in util::command::new_smol_command and util::set_pre_exec_to_start_new_session, but PTY child spawning in alacritty_terminal was not covered.

This PR updates alacritty_terminal to include PTY pre_exec exception-port reset:
zed-industries/alacritty@9d9640d

Upstream:

• macOS: Reset Mach exception ports in PTY child pre_exec alacritty/alacritty#8835

Release Notes:

• Fixed terminal tasks hanging on macOS when a spawned process is killed by a signal.