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.

git-svn-id: https://develop.svn.wordpress.org/trunk@47557 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/screen.php

@@ -128,10 +128,12 @@ function meta_box_prefs( $screen ) {
 					$widget_title = $box['args']['__widget_basename'];
 				}
 
+				$is_hidden = in_array( $box['id'], $hidden, true );
+
 				printf(
 					'<label for="%1$s-hide"><input class="hide-postbox-tog" name="%1$s-hide" type="checkbox" id="%1$s-hide" value="%1$s" %2$s />%3$s</label>',
 					esc_attr( $box['id'] ),
-					checked( in_array( $box['id'], $hidden, true ), false, false ),
+					checked( $is_hidden, false, false ),
 					$widget_title
 				);
 			}