Cast wp_count_attachments() before iterating it to avoid a notice when items exist without a mime type.

props bobbingwide.
fixes #27802.

Built from https://develop.svn.wordpress.org/trunk@28139


git-svn-id: http://core.svn.wordpress.org/trunk@27970 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add missing string translation in widgets.

see #27453, #27112.

Built from https://develop.svn.wordpress.org/trunk@28140


git-svn-id: http://core.svn.wordpress.org/trunk@27971 1a063a9b-81f0-0310-95a4-ce76da25c4cd