cp does not detect that a container is `--read-only`, and lets tar fail through in some cases

[apostasie]

Description

Title says all.

Steps to reproduce the issue

Start a container read-only. cp into it

Similarly to #3313 there is a mechanism to detect that in some cases - just not for when the container is running.

Describe the results you received and expected

na

What version of nerdctl are you using?

main

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

None

Host information

No response