Follow up to https://github.com/zed-industries/zed/pull/57632, uses
changes from https://github.com/zed-industries/zed/pull/58061

Previously the floating permission popover only appeared when the inline
permission prompt was scrolled below the viewport. It now also appears
when the prompt is scrolled above the viewport, with the scroll button
pointing in the right direction.

Release Notes:

- Fixed the agent permission popover not appearing when the inline
prompt was scrolled above the viewport.