Closes #9418 

Noticed a difference in the `cx.set_tooltip(...)` calls between `div`
and `InteractiveText`. `div` calls `cx.set_tooltip(...)` inside
`after_layout`, but `InteractiveText` was calling this inside `paint`. I
believe as #9012 was merged, we need to call `cx.set_tooltip` inside
`after_layout`, as inserting inside `paint` does not seem to be
supported anymore.

I moved the code for setting the tooltip to `after_layout` and hovering
over links inside the chat seems to bring up the tooltips again.

Before:

See https://github.com/zed-industries/zed/issues/9418#issue-2189398784

After:


![image](https://github.com/zed-industries/zed/assets/53836821/a623164c-1ce0-40d7-bc53-020f176fba4a)


Release Notes:

- Fixed tooltip not showing up when hovering over links inside the chat
panel ([#9418](https://github.com/zed-industries/zed/issues/9418))