Formatting: Filter out the bullet character in `sanitize_title_with_dashes()`.

Props roytanck, deepaklalwani, veromary.
Fixes #49791.
Built from https://develop.svn.wordpress.org/trunk@48593


git-svn-id: https://core.svn.wordpress.org/trunk@48355 1a063a9b-81f0-0310-95a4-ce76da25c4cd