Can't collect directory within container

[pmoravec]

When calling something like:

self.add_copy_spec(["/etc/foreman/", container='foreman')

then it fails with:

Traceback (most recent call last):
  File "/blah/sos/report/__init__.py", line 1385, in collect_plugin
    plug.collect_plugin()
  File "/blah/sos/report/plugins/__init__.py", line 3344, in collect_plugin
    self._collect_container_copy_specs()
  File "/blah/sos/report/plugins/__init__.py", line 3213, in _collect_container_copy_specs
    self.archive.check_path(arcdest, P_FILE)
  File "/blah/sos/archive.py", line 328, in check_path
    raise ValueError(ve_msg % (dest, f"regular file, for {src=} and {dest=}"))
ValueError: path '/var/tmp/sos.28fzpusb/sosreport-blah-2025-12-20-omtrsgs/sos_containers/foreman/etc/foreman/' exists and is not a regular file

The reason is https://github.com/sosreport/sos/blob/main/sos/report/plugins/__init__.py#L3213 assumes we collect just files (neither dir or symlink or special file).