test(redis): cover a backslash in list_sessions glob escaping

[vishal-bulbule]

Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• N/A

2. Or, if no issue exists, describe the change:

This is the follow-up test a maintainer asked for in
#6956:
"the backslash case still isn't covered, so that test is worth sending on its own."

Problem:

4b26bba made RedisSessionService.list_sessions match app_name and user_id literally by
escaping Redis glob metacharacters. _escape_glob escapes the backslash along with *, ?,
[ and ], but test_list_sessions_glob_metacharacters_match_literally had no backslash
case. User IDs such as CORP\alice depend on it.

Solution:

Add a backslash case to the existing test's table in
tests/unittests/integrations/redis/test_redis_session_service.py. Test-only change.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

The new case passes on main, and fails if the backslash is removed from _escape_glob
(checked by temporarily editing the regex):

$ pytest tests/unittests/integrations/redis -k glob_metacharacters
1 passed
(with the backslash removed from _escape_glob: 1 failed)

$ pytest tests/unittests -n auto
15287 passed, 1 failed

$ tox   (Python 3.10, 3.11, 3.12, 3.13, 3.14)
py310: 15221 passed, 1 failed
py311: 15230 passed, 1 failed
py312: 15221 passed, 1 failed
py313: 15221 passed, 1 failed
py314: 15221 passed, 1 failed

The one failing test below, test_import_loading.py::test_entry_point_loads_only_allowlisted_packages[agent],
also fails on main (d57c84f) and is unrelated to this change; #7214 fixes it.

Manual End-to-End (E2E) Tests:

N/A, test-only change.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas. (N/A, test-only)
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end. (N/A, test-only)
• Any dependent changes have been merged and published in downstream modules. (N/A)