Themes: A11y: Fix scroll jump when closing modal navigation.

Fix an issue where navigation and search modals triggered an undesirable scroll behavior if triggered while the page was not scrolled all the way to the top.

Props kjellr, nikunj8866, sabernhardt, karmatosed, sainathpoojary, joedolson.
Fixes #52116.

git-svn-id: https://develop.svn.wordpress.org/trunk@60280 602fd350-edb4-49c9-b593-d223f7449a82

Author: joedolson

src/wp-content/themes/twentytwenty/assets/js/index.js

@@ -257,7 +257,10 @@ twentytwenty.coverModals = {
 						clickedEl = false;
 					}
 
-					_win.scrollTo( 0, Math.abs( _win.twentytwenty.scrolled + getAdminBarHeight() ) );
+					_win.scrollTo({
+						top: Math.abs( _win.twentytwenty.scrolled + getAdminBarHeight() ),
+						behavior: 'instant'
+					});
 
 					_win.twentytwenty.scrolled = 0;
 				}, 500 );