Welcome: Only count internal callbacks as steps (#1942)

Author: obenland

.github/changelog/1942-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: changed
+
+Step counts for the Welcome checklist now only take into account steps that are added in the Welcome class.

includes/wp-admin/class-welcome-fields.php

@@ -139,7 +139,11 @@ private static function get_total_steps_count() {
 		$count = 0;
 
 		if ( isset( $wp_filter['activitypub_onboarding_steps'] ) ) {
-			$count = \count( $wp_filter['activitypub_onboarding_steps']->callbacks );
+			$pattern = '/^' . \preg_quote( self::class, '/' ) . '/';
+			foreach ( $wp_filter['activitypub_onboarding_steps']->callbacks as $callbacks ) {
+				$matching_keys = \preg_grep( $pattern, \array_keys( $callbacks ) );
+				$count        += \count( $matching_keys );
+			}
 		}
 
 		return $count;