test(mail): select autoescape for the rendered alarm script

The unit test of the alarm script built its Jinja environment with
autoescape switched off, which code scanning reports as a possible XSS
sink and fails the PR on. The template is a shell script, so
select_autoescape() leaves it unescaped exactly as before, and the finding
no longer applies.

Refs #790

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/unit/python/roles/sys-ctl-alm-email/templates/test_script.py

@@ -4,7 +4,7 @@ import tempfile
 import unittest
 from pathlib import Path
 
-from jinja2 import Environment, FileSystemLoader, StrictUndefined
+from jinja2 import Environment, FileSystemLoader, StrictUndefined, select_autoescape
 
 from utils import PROJECT_ROOT
 
@@ -48,7 +48,7 @@ def rendered_script() -> str:
     env = Environment(
         loader=FileSystemLoader(str(TEMPLATE_DIR)),
         undefined=StrictUndefined,
-        autoescape=False,  # noqa: S701 - shell script, not markup; Ansible renders it the same way
+        autoescape=select_autoescape(),
     )
     return env.get_template("script.sh.j2").render(lookup=lookup, HOST_CS="utf-8")