Site Health: Remove unused `$wpdb` global in `utf8mb4` support test.

Follow-up to [44984], [56475].

Props upadalavipul, mukesh27.
Fixes #59977.
Built from https://develop.svn.wordpress.org/trunk@57141


git-svn-id: http://core.svn.wordpress.org/trunk@56652 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-site-health.php

@@ -1288,13 +1288,9 @@ class WP_Site_Health {
 	 *
 	 * @since 5.2.0
 	 *
-	 * @global wpdb $wpdb WordPress database abstraction object.
-	 *
 	 * @return array The test results.
 	 */
 	public function get_test_utf8mb4_support() {
-		global $wpdb;
-
 		if ( ! $this->mysql_server_version ) {
 			$this->prepare_sql_data();
 		}

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57140';
+$wp_version = '6.5-alpha-57141';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.