Some improvements to the dashboard activity widget:

* Use the correct background color for unapproved comments.
* Use the sale box-shadow style instead of a border between rows so the orange border is uninterrupted between multiple pending comments.

See #25858.



git-svn-id: https://develop.svn.wordpress.org/trunk@26297 602fd350-edb4-49c9-b593-d223f7449a82