bpo-40477: macOS Python Launcher app fixes for recent macOS releases (GH-30348) (GH-30349)

This change solves two problems encountered by users of the macOS Python Launcher app on recent macOS releases (10.14+):

- The launcher app was no longer able to launch the macOS Terminal.app to run a script.

- Even if Terminal.app was already launched, the launcher app was unable to send an Apple Event to Terminal.app to open and run Python with the desired .py file.
(cherry picked from commit 549e62827262264cda30455e10e315602129da72)

Co-authored-by: Ned Deily <nad@python.org>