Media modal: fix reordering of the thumbnails while creating or editing a gallery, props avryl, fixes #29606 for trunk. 
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git-svn-id: http://core.svn.wordpress.org/trunk@29633 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Differentiate between invalid and missing admin emails when adding a new site

Check the emptiness of the admin email before using `sanitize_email()` and `is_email()` to determine if the address is valid.

Fixes #17890

Built from https://develop.svn.wordpress.org/trunk@29877


git-svn-id: http://core.svn.wordpress.org/trunk@29634 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Quicktags: remove `accesskey` attributes the buttons and don't add empty `title` attributes, fixes #29358
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git-svn-id: http://core.svn.wordpress.org/trunk@29635 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix support for the `hide` option in wpColorPicker, props tollmanz, fixes #29632
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git-svn-id: http://core.svn.wordpress.org/trunk@29636 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Do not send a welcome notification when noconfirmation has been flagged

When adding a new user to a site on the network, 2 emails are sent out - one for confirmation and one as a welcome. If the option for no confirmation is selected, neither should send.

props transom
Fixes #16235

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git-svn-id: http://core.svn.wordpress.org/trunk@29637 1a063a9b-81f0-0310-95a4-ce76da25c4cd