Fix bookmarks toolbar behaviour with Sync Promo on iOS 15 (#3313)

Task/Issue URL: https://app.asana.com/0/414709148257752/1208220515829639/f
Tech Design URL:
CC:

Description:
Fixes a SwiftUI issue which caused the toolbar to not appear correctly on the bookmarks screen (iOS 15 only)

DuckDuckGo/BookmarksViewController.swift

@@ -897,9 +897,18 @@ class BookmarksViewController: UIViewController, UITableViewDelegate {
             }
 
             syncPromoViewHostingController.view.translatesAutoresizingMaskIntoConstraints = false
-            addChild(syncPromoViewHostingController)
+
+            // This is needed to ensure the toolbar displays correctly on iOS 15
+            if #available(iOS 16.0, *) {
+                addChild(syncPromoViewHostingController)
+            }
+
             headerView.addSubview(syncPromoViewHostingController.view)
 
+            if #available(iOS 16.0, *) {
+                syncPromoViewHostingController.didMove(toParent: self)
+            }
+
             NSLayoutConstraint.deactivate([
                 searchBarBottomConstraint
             ])
@@ -920,9 +929,6 @@ class BookmarksViewController: UIViewController, UITableViewDelegate {
             headerView.frame = CGRect(x: 0, y: 0, width: tableView.bounds.width, height: totalHeight)
 
             tableView.tableHeaderView = headerView
-            syncPromoViewHostingController.didMove(toParent: self)
-
-            tableView.layoutIfNeeded()
         } else if !headerView.subviews.contains(searchBar) || headerView.subviews.count != 1 {
 
             if syncPromoViewHostingController.view != nil {

DuckDuckGo/SyncAssets.xcassets/Sync-Downloads-24.imageset/Contents.json

@@ -8,5 +8,8 @@
   "info" : {
     "author" : "xcode",
     "version" : 1
+  },
+  "properties" : {
+    "template-rendering-intent" : "template"
   }
 }