Coding Standards: Use strict type check for `in_array()` and `array_search()`.

This addresses all the remaining `WordPress.PHP.StrictInArray.MissingTrueStrict` issues in core.

Includes minor code layout fixes for better readability.

Follow-up to [47550].

See #49542.
Built from https://develop.svn.wordpress.org/trunk@47557


git-svn-id: https://core.svn.wordpress.org/trunk@47332 1a063a9b-81f0-0310-95a4-ce76da25c4cd