last cell of scrollbar isn't shown when winbar is set

[0xAdk]

Describe the bug when a winbar is present the scollbar's bottom most cell isn't show / is draw off the window.

This results in things like

• diagnostic info / search matches not being present in the scrollbar.
• the scollbar not being drawn at all when it's one cell tall and you are near the end of a very long file (7000+)

To Reproduce using search match as an example: open nvim run exe 'norm 200o' | exe 'norm itest' | /test then either

enable winbar set winbar=winbar and refresh scollbar :SatelliteRefresh the search match isn't shown in the scrollbar

disable winbar set winbar= and refresh scollbar :SatelliteRefresh the search match is shown in the scrollbar

Expected behavior the search match is show at the bottom of the scollbar