[Plugin] Check if a path exists inside a container in add_dir_listing()

[jcastill]

Currently, add_dir_listing() checks if a path exists outside of a container, and when we call the command for a container, it fails to collect any listing. This patch adds a new function container_path_exists() that checks for the specified path in add_dir_listing() inside the container.

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[jcastill]

I'm sure there are better ways to do this, but I didn't find any way in our code already, so I had to come up with this 'dirty' trick.
As always, open to suggestions to do this in a better way :)

[packit-as-a-service]

Congratulations! One of the builds has completed. 🍾

You can install the built RPMs by following these steps:

• sudo yum install -y dnf-plugins-core on RHEL 8
• sudo dnf install -y dnf-plugins-core on Fedora
• dnf copr enable packit/sosreport-sos-3805
• And now you can install the packages.

Please note that the RPMs should be used only in a testing environment.

[pmoravec]

ACK in general. I would expect there is more elegant solution than the self.exec_cmd(f"test -e {path}", container=container) but I cant find any /o.