shell: skip playing unplayable uri entries in command line
Attempting to play 'ignore' and 'import-error' entries result in incorrect code paths, which deal with empty metadata for the entries, causing invalid file path calculation resulting in filesystem permission issues.
This should also get rid of "Problem occurred without error being set. This is a bug in Rhythmbox or GStreamer" message, which happens when we try to play an unplayable entry.
Closes: #1451 (closed)