Administration: Fix increasing of the frequency of Heartbeat API requ…

…ests.

Props peterwilsoncc, azaozz.
Fixes #61960.

git-svn-id: https://develop.svn.wordpress.org/trunk@59092 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/edit-form-blocks.php

@@ -126,9 +126,10 @@ static function ( $classes ) {
 // Set Heartbeat interval to 10 seconds, used to refresh post locks.
 wp_add_inline_script(
 	'heartbeat',
-	'if ( window.wp && window.wp.heartbeat ) {
-		window.wp.heartbeat.interval( 10 );
-	}'
+	'jQuery( function() {
+		wp.heartbeat.interval( 10 );
+	} );',
+	'after'
 );
 
 /*