In `$wpdb->update()`, prevent explosions when `$where` is empty.

Adds unit tests.

Props UmeshSingla, wonderboymusic.
Fixes #26106

Built from https://develop.svn.wordpress.org/trunk@28814


git-svn-id: http://core.svn.wordpress.org/trunk@28621 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add a filter/docs: 'oembed_remote_get_args' to `WP_oEmbed->discover()` and `->_fetch_with_format()`.

Props leewillis77, DrewAPicture.
Fixes #23442.

Built from https://develop.svn.wordpress.org/trunk@28815


git-svn-id: http://core.svn.wordpress.org/trunk@28622 1a063a9b-81f0-0310-95a4-ce76da25c4cd