Correct the width of the background vignette in the plugin info modal.

Fixes #28229

Built from https://develop.svn.wordpress.org/trunk@30700


git-svn-id: http://core.svn.wordpress.org/trunk@30690 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revert r30115 which was a breaking change for code which interacts with the return value of `get_metadata()` when no meta key is specified.

See #15030

Built from https://develop.svn.wordpress.org/trunk@30701


git-svn-id: http://core.svn.wordpress.org/trunk@30691 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Update the tests for `get_metadata()` to reflect the revert in r30701.

See #15030

Built from https://develop.svn.wordpress.org/trunk@30702


git-svn-id: http://core.svn.wordpress.org/trunk@30692 1a063a9b-81f0-0310-95a4-ce76da25c4cd