recent projects: fix list flashing/empty (#8376)

If the list is large (size > overdraw + available height) the
`all_rendered` check was preventing the list from returning an inferred
size. Theoretically we can now report heights which are actually too
small (because not all items were affected during layout), this can be
manually adjusted using the overdraw parameter. In this case its fine
because the picker is inside a max_height which should never be more
then the overdraw we specify (1000 px), and the list will shrink down
either way when the request_measured_layout callback is called again.

Release Notes:

- Fixed flashing of recent projects list when there were a lot of
projects in the list
([#8364](https://github.com/zed-industries/zed/issues/8364#issuecomment-1962849393)).