Remove no longer needed placeholder
Remove no longer needed placeholder

Now the chat tab is not displayed for folders, so the placeholder that
was shown in that case can be removed.

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed