docs(k8s): add a note about multi-container pods

[afdesk]

Description

Now #7444 is merged, we should clarify the position about association the result with the metadata for multi-container pdos. this PR adds a small note about it.

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).