SEO tools suite loading even if the site is not active and not in dev…

…elopment mode. (#7900)

* Added seo tools suite loading even if the site is not active and not in development mode.

This is required because with some recent changes in the code SEO tool class constants are required by the code even when Jetpack is not active, for example in multisite environment.

Fixes #7898.

* Improved condition readability and clarified a filter comment.

class.jetpack.php

@@ -1654,10 +1654,15 @@ function user_role_change( $user_id ) {
 	 * Loads the currently active modules.
 	 */
 	public static function load_modules() {
-		if ( ! self::is_active() && !self::is_development_mode() ) {
-			if ( ! is_multisite() || ! get_site_option( 'jetpack_protect_active' ) ) {
-				return;
-			}
+		if (
+			! self::is_active()
+			&& ! self::is_development_mode()
+			&& (
+				! is_multisite()
+				|| ! get_site_option( 'jetpack_protect_active' )
+			)
+		) {
+			return;
 		}
 
 		$version = Jetpack_Options::get_option( 'version' );
@@ -1734,8 +1739,7 @@ public static function load_modules() {
 		do_action( 'jetpack_modules_loaded' );
 
 		// Load module-specific code that is needed even when a module isn't active. Loaded here because code contained therein may need actions such as setup_theme.
-		if ( Jetpack::is_active() || Jetpack::is_development_mode() )
-			require_once( JETPACK__PLUGIN_DIR . 'modules/module-extras.php' );
+		require_once( JETPACK__PLUGIN_DIR . 'modules/module-extras.php' );
 	}
 
 	/**

modules/module-extras.php

@@ -27,10 +27,20 @@
 	'verification-tools/verification-tools-utils.php',
 );
 
+// Not every tool needs to be included if Jetpack is inactive and not in development mode
+if ( ! Jetpack::is_active() && ! Jetpack::is_development_mode() ) {
+	$tools = array(
+		'seo-tools/jetpack-seo-utils.php',
+		'seo-tools/jetpack-seo-titles.php',
+		'seo-tools/jetpack-seo-posts.php',
+	);
+}
+
 /**
  * Filter extra tools (not modules) to include.
  *
  * @since 2.4.0
+ * @since 5.4.0 can be used in multisite when Jetpack is not connected to WordPress.com and not in development mode.
  *
  * @param array $tools Array of extra tools to include.
  */