Coding Standards: Use strict comparison in wp-admin/network where static strings are involved.

Includes minor code layout fixes for better readability.

Follow-up to [47808].

See #49542.
Built from https://develop.svn.wordpress.org/trunk@47853


git-svn-id: http://core.svn.wordpress.org/trunk@47629 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/network/plugin-install.php

@@ -7,7 +7,7 @@
  * @since 3.1.0
  */
 
-if ( isset( $_GET['tab'] ) && ( 'plugin-information' == $_GET['tab'] ) ) {
+if ( isset( $_GET['tab'] ) && ( 'plugin-information' === $_GET['tab'] ) ) {
 	define( 'IFRAME_REQUEST', true );
 }