Popup position fix for iPhone (#3440)

* add a condition for when the nav promo offset is subtracted from the top of the popup

* fixed popup height for iphone

* moved the popup 1px up

libs/blocks/global-navigation/global-navigation.js

@@ -1175,10 +1175,11 @@ class Gnav {
             // at this point by calling disableMobileScroll
             if (popup && this.isLocalNav()) {
               const y = window.scrollY;
+              const iOSy = Math.abs(parseInt(document.body.style.top, 10));
               const offset = this.block.classList.contains('has-promo')
                 ? 'var(--feds-height-nav) - var(--global-height-navPromo)'
                 : 'var(--feds-height-nav)';
-              popup.style = `top: calc(${y || 0}px - ${offset}`;
+              popup.style = `top: calc(${iOSy || y || 0}px - ${offset} - 1px`;
             }
             makeTabActive(popup);
           } else if (isDesktop.matches && this.newMobileNav && isSectionMenu) {