Install Plugins: Don't wp_die() if API can't be reached.

props johnbillion.
fixes #29361.
Built from https://develop.svn.wordpress.org/trunk@29594


git-svn-id: http://core.svn.wordpress.org/trunk@29368 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Plugins: Only show details link if user can install plugins.

fixes #17902.

Built from https://develop.svn.wordpress.org/trunk@29595


git-svn-id: http://core.svn.wordpress.org/trunk@29369 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Make filter bar CSS less verbose and redundant.

Also removes an unused handler in the theme feature filter.

see #28794.

Built from https://develop.svn.wordpress.org/trunk@29596


git-svn-id: http://core.svn.wordpress.org/trunk@29370 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Only show one search form for the plugin installer.

The field dropdown now appears in the filter bar only when doing a search.

see #28785.

Built from https://develop.svn.wordpress.org/trunk@29597


git-svn-id: http://core.svn.wordpress.org/trunk@29371 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: Move CSS into an admin-only file.

`media-views.css` can be loaded on the front, which does not need this extra CSS.

fixes #29340.

Built from https://develop.svn.wordpress.org/trunk@29598


git-svn-id: http://core.svn.wordpress.org/trunk@29372 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Send nocache_headers() on installation screens and when redirecting to them.

fixes #29248.
Built from https://develop.svn.wordpress.org/trunk@29599


git-svn-id: http://core.svn.wordpress.org/trunk@29373 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: exit selection mode when Esc is pressed.

Fixes #29366.

Built from https://develop.svn.wordpress.org/trunk@29600


git-svn-id: http://core.svn.wordpress.org/trunk@29374 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media: when activating a mode after [29056], don't trigger the `{mode}:activate` event twice in a row.

See #29366.

Built from https://develop.svn.wordpress.org/trunk@29601


git-svn-id: http://core.svn.wordpress.org/trunk@29375 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media: cleanup recent changes to `media.view.FocusManager`.

* Adjusts the focus method to target the menu for the current modal
* Refactor the FocusManager so that the method names and the functionality matches more closely with how it currently works. The changes in 4.0 to the FocusManager change the purpose of the focus manager entirely — instead of being a way to save and restore focus state, the new FocusManager is about constraining keyboard navigation via the tab key to inside the modal. 

Props gcorne.
See #23560.

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git-svn-id: http://core.svn.wordpress.org/trunk@29376 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media modal: when inserting content, prefer the editor id passed while opening the modal. wpActiveEditor can change in the background. (Includes some precommit prefixed selectors.) Fixes #28173
Built from https://develop.svn.wordpress.org/trunk@29603


git-svn-id: http://core.svn.wordpress.org/trunk@29377 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Correct cascade oversights in form CSS. fixes #28262.

Built from https://develop.svn.wordpress.org/trunk@29604


git-svn-id: http://core.svn.wordpress.org/trunk@29378 1a063a9b-81f0-0310-95a4-ce76da25c4cd