Download button is the same of download bubble

[Admini]

It is finished. My other browser uses Chromium/Blink version 109 which has two non-experimental flags about the download bubble. Also it isn't marked as experimental in CentBrowser flag description.

Another problem is that the download bubble is much simpler than the current one.
For example, search task and delete single task are missing..
We still need to add them back.