[CI]: TestRunStargz is racy

### Description

`ls: cannot access '/.stargz-snapshotter': No such file or directory`

I assume this is mounted somehow after some stargz daemon initializes?

### Steps to reproduce the issue

1.
2.
3.

### Describe the results you received and expected

```
=== FAIL: cmd/nerdctl/container TestRunStargz (36.06s)
command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test info --format {{ json . }}
container_run_stargz_linux_test.go:42:
container_run_stargz_linux_test.go:42: ======================== Pre-test cleanup ========================
container_run_stargz_linux_test.go:42:
container_run_stargz_linux_test.go:42: ======================== Test setup ========================
container_run_stargz_linux_test.go:42:
container_run_stargz_linux_test.go:42: ======================== Test Run ========================
command.go:113: /usr/local/bin/nerdctl --namespace=nerdctl-test --snapshotter=stargz run --rm ghcr.io/stargz-containers/fedora:30-esgz ls /.stargz-snapshotter
command.go:113: Expected exit code: 0

Command: /usr/local/bin/nerdctl --namespace=nerdctl-test --snapshotter=stargz run --rm ghcr.io/stargz-containers/fedora:30-esgz ls /.stargz-snapshotter
ExitCode: 2
Error: exit status 2

```

` ls: cannot access '/.stargz-snapshotter': No such file or directory`

### What version of nerdctl are you using?

main

### Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

### Host information

_No response_