Twenty Twenty: Menu + Search can cause a scroll jump on close

[kjellr]

If the Twenty Twenty Menu or Search modals are activated while the user is partially scrolled down the page, they will cause a glitchy reaction upon close: the page quickly scrolls to the top, and then back down to the original position. This is visible in Chrome or Firefox, but doesn't seem visible in Safari.

Here are some GIFs to illustrate the issue:

Originally noted in the [support forums ​https://wordpress.org/support/topic/toggle-close-search-menu-rapidly-scrolls-glitch/].

[sabernhardt]

This relates to the scrollTo function inside a setTimeout, within hideAndShowModals.