FIX: iPad DiscourseHub app layout issues (#11048)

- fixes height of user dropdown menu
- fixes offset when jumping to a post
- removes landscape-specific CSS padding (following a fix in the app repo)

app/assets/javascripts/discourse/app/components/site-header.js

@@ -347,11 +347,19 @@ const SiteHeaderComponent = MountWidget.extend(Docking, PanEvents, {
           height = winHeight - menuTop;
         }
 
+        const isIPadApp = document.body.classList.contains("footer-nav-ipad"),
+          heightProp = isIPadApp ? "max-height" : "height",
+          iPadOffset = 10;
+
+        if (isIPadApp) {
+          height = winHeight - menuTop - iPadOffset;
+        }
+
         if ($panelBody.prop("style").height !== "100%") {
           $panelBody.height("100%");
         }
-        if (style.top !== menuTop + "px" || style.height !== height) {
+        if (style.top !== menuTop + "px" || style[heightProp] !== height) {
-          $panel.css({ top: menuTop + "px", height });
+          $panel.css({ top: menuTop + "px", [heightProp]: height });
           $(".header-cloak").css({ top: menuTop + "px" });
         }
         $("body").removeClass("drop-down-mode");

app/assets/javascripts/discourse/app/lib/offset-calculator.js

@@ -3,8 +3,11 @@ export function scrollTopFor(y) {
 }
 
 export function minimumOffset() {
-  const header = document.querySelector("header.d-header");
+  const header = document.querySelector("header.d-header"),
-  return header ? header.offsetHeight : 0;
+    iPadNav = document.querySelector(".footer-nav-ipad .footer-nav"),
+    iPadNavHeight = iPadNav ? iPadNav.offsetHeight : 0;
+
+  return header ? header.offsetHeight + iPadNavHeight : 0;
 }
 
 export default function offsetCalculator() {

app/assets/stylesheets/common/components/footer-nav.scss

@@ -86,18 +86,4 @@ body.footer-nav-ipad {
   &.docked .d-header-wrap {
     top: $footer-nav-height;
   }
-
-  @media only screen and (orientation: landscape) {
-    $status-bar-padding: 12px;
-
-    padding-top: $footer-nav-height + $status-bar-padding;
-
-    .footer-nav {
-      padding-top: $status-bar-padding;
-    }
-
-    &.docked .d-header-wrap {
-      top: $footer-nav-height + $status-bar-padding;
-    }
-  }
 }