Import-check may return error saying "director does not exist" when it actually just lack permissions

[jpasqualetto]

Endpoint /pulp/api/v3/importers/core/pulp/import-check/ returns error saying "Directory does not exist" when pulp user lack permissions to read said directory.

To Reproduce

Try importing content from a directory where pulp user doesn't have read access.

Expected behavior
Error returned should indicate the permission error.

Additional context

Pulp is using os.path.exists() method to verify if the directory exists: https://github.com/pulp/pulpcore/blob/main/pulpcore/app/views/importer.py#L44-L45

However, the method can return false if permission is not granted to access the directory even if the directory exists

os.path.exists(path)
Return True if path refers to an existing path or an open file descriptor. Returns False for broken symbolic links. On some platforms, this function may return False if permission is not granted to execute os.stat() on the requested file, even if the path physically exists.

os.path method documentation -> https://docs.python.org/3/library/os.path.html

[pulpbot]

https://bugzilla.redhat.com/show_bug.cgi?id=2232625