All destructive row actions should be styled as such.

This fixes spam and trash links in the dashboard activity widget.

props avryl.
fixes #27370.

Built from https://develop.svn.wordpress.org/trunk@27547


git-svn-id: http://core.svn.wordpress.org/trunk@27390 1a063a9b-81f0-0310-95a4-ce76da25c4cd