Like commit 55749af0c7 but for podman *pod* stats not the normal podman
stats. We must ignore ErrCtrStopped here as well as this will happen
when the container process exited.
While at it remove a useless argument from the function as it was always
nil and restructure the logic flow to make it easier to read.
Fixes#23334
Signed-off-by: Paul Holzinger <pholzing@redhat.com>