Update leftbar generic needle, add rhbz#1959160 workaround
    
    The background color of the generic left bar needle has changed
    to match the new logo base color. The top bar's background color
    has similarly changed, but this also caused us to notice a bug
    in fedora-logos - that topbar image file seems to be basically
    empty (just a transparent rectangle) so we see no 'image' in the
    top bar, just solid electric blue. This needle matches that.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>