Add patch '15-cinderx-site-import' to third-party/python/3.14

Summary:
This diff adds a patch to the `third-party/python/3.14` Meta-internal fork.

Import init_cinderx in sitecustomize

Reviewed By: yoney

Differential Revision: D86314368

fbshipit-source-id: e6eddc821e2850f6eedee6cde340a6ead99330a6

Author: DinoV

cinderx/PythonLib/test_cinderx/test_jitlist.py

@@ -276,10 +276,7 @@ def test_fail_on_parse_error_startup(self) -> None:
                 env={"PYTHONPATH": CINDERX_PATH},
             )
 
-        # Python 3.14 raises and logs the exception, but doesn't exit with a non-zero
-        # error code.
-        if sys.version_info[:2] < (3, 14):
-            self.assertNotEqual(proc.returncode, 0, proc)
+        self.assertNotEqual(proc.returncode, 0, proc)
 
         self.assertIn("Error while parsing line", proc.stderr)
         self.assertIn("in JIT list file", proc.stderr)