test: fix pull failure assertion for Docker v29

[ricardobranco777]

What I did

Fix pull failure assertion for Docker v29.2

The error message comes now from containerd.

Related issue

#13565

Otherwise test fails with:

=== RUN   TestComposePull/Verify_pull_failure
    pull_test.go:68: Running command: /usr/lib/docker/cli-plugins/docker-compose --project-directory fixtures/compose-pull/unknown-image pull
    pull_test.go:69: assertion failed: 
        Command:  /usr/lib/docker/cli-plugins/docker-compose --project-directory fixtures/compose-pull/unknown-image pull
        ExitCode: 1
        Error:    exit status 1
        Stdout:   
        Stderr:    Image does_not_exists Pulling 
         Image doesn_t_exists_either Pulling 
         Image alpine:3.15 Pulling 
         Image alpine:3.15 Pulled 
         Image doesn_t_exists_either failed to resolve reference "docker.io/library/doesn_t_exists_either:latest": docker.io/library/doesn_t_exists_either:latest: not found 
         Image does_not_exists Error failed to resolve reference "docker.io/library/does_not_exists:latest": docker.io/library/does_not_exists:latest: not found
        time="2026-01-30T08:23:20-05:00" level=warning msg="WARNING: Some service image(s) must be built from source by running:\n    docker compose build can_build"
        Error response from daemon: failed to resolve reference "docker.io/library/does_not_exists:latest": docker.io/library/does_not_exists:latest: not found
        
        
        Failures:
        Expected stderr to contain "pull access denied for does_not_exists"
    --- FAIL: TestComposePull/Verify_pull_failure (0.92s)
FAIL pkg/e2e.TestComposePull/Verify_pull_failure (0.92s)