docs: make sure that channels use finally in all examples

[sobolevn]

Right now this code:

Is not really correct, because in case of an exception - it will not execute await channels.unsubscribe(subscriber, ["foo"]), which might be unexpected.

There's a similar example above that use the correct form:

[sobolevn]

This failure does not look related: https://github.com/litestar-org/litestar/actions/runs/11330520189/job/31508525457?pr=3796

==================================== ERRORS ====================================
_______________ ERROR at setup of test_with_stores[redis_store] ________________
[gw0] linux -- Python 3.12.7 /home/runner/work/litestar/litestar/.venv/bin/python

request = <SubRequest 'store' for <Coroutine test_with_stores[redis_store]>>

    @pytest.fixture(
        params=[pytest.param("redis_store", marks=pytest.mark.xdist_group("redis")), "memory_store", "file_store"]
    )
    def store(request: FixtureRequest) -> Store:
>       return cast("Store", request.getfixturevalue(request.param))

tests/conftest.py:111: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
.venv/lib/python3.12/site-packages/pytest_asyncio/plugin.py:369: in _async_fixture_wrapper
    return event_loop.run_until_complete(setup())
/opt/hostedtoolcache/Python/3.12.7/x64/lib/python3.12/asyncio/base_events.py:687: in run_until_complete
    return future.result()
.venv/lib/python3.12/site-packages/pytest_asyncio/plugin.py:364: in setup
    res = await func(
tests/docker_service_fixtures.py:127: in redis_service
    await docker_services.start("redis", check=redis_responsive)
tests/docker_service_fixtures.py:80: in start
    self.run_command("up", "-d", name)
tests/docker_service_fixtures.py:68: in run_command
    subprocess.run(command, check=True, capture_output=True)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

input = None, capture_output = True, timeout = None, check = True
popenargs = (['docker', 'compose', '--file=/home/runner/work/litestar/litestar/tests/docker-compose.yml', '--project-name=litestar_pytest-gw0', 'up', '-d', ...],)
kwargs = {'stderr': -1, 'stdout': -1}
process = <Popen: returncode: 18 args: ['docker', 'compose', '--file=/home/runner/work...>
stdout = b''
stderr = b'time="2024-10-14T15:24:33Z" level=warning msg="/home/runner/work/litestar/litestar/tests/docker-compose.yml: `versio...l rate limit. You may increase the limit by authenticating and upgrading: [https://www.docker.com/increase-rate-limit\n](https://www.docker.com/increase-rate-limit/n)'
retcode = 18

[sobolevn]

@Alc-Alc can you please take a look? :)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/litestar-docs-preview/3796

[Alc-Alc]

@Alc-Alc can you please take a look? :)

finally did 😅 thank you 🙂