dock: Fix to sync active state to panels when collapse dock.

[JakkuSakura]

This is a continuation of #764
Without this, if we drag webview to sidebar and collapse, webview is not aware of itself being hidden

[huacnlee]

You don't have to follow up and insert the WebView into the Panel. This will cause many problems, WebView used into GPUI there have a lot of limit.

Actually in our application, we only use WebView to render into a Drawer or a Modal.

[huacnlee]

And I also removed WebView story in PR #769 from the main example application, because if we enable this, the WebView will cause some unexpected problems (For example: It will get the focus handle in high priority, this will break the general element's events).

[JakkuSakura]

I see. This PR is clean though. It doesn't add WebView anywhere. It just fixes the relevant issue

[huacnlee]

I have done a test, this change is not correct. When I collapse a bottom dock, the log is display like:

panel: Image active: true
panel: Icon active: true
panel: Image active: false
panel: Icon active: false
panel: Image active: true
panel: Icon active: true
panel: Tooltip active: true

[JakkuSakura]

What should be the correct output?

[huacnlee]

You can test it, the log is unexpected.

[JakkuSakura]

Ah I see. Fixed now

[huacnlee]

Thanks.