Closes https://github.com/zed-industries/zed/issues/43292

We were seeing clicks on the "View Panel" and "Dismiss" buttons
sometimes not being triggered. I believe this was happening because the
overall parent also had an on_click, which due to this being a popup
window, was causing conflicts with the buttons' on click handlers. This
should hopefully fix that issue.

Release Notes:

- agent: Fixed an issue where clicking on the agent notification buttons
would sometimes not trigger their actions.