Fixes hotkey for navigation between apps and content apps

Fixes https://github.com/umbraco/Umbraco-CMS/issues/4757

src/Umbraco.Web.UI.Client/src/common/directives/components/editor/umbeditornavigationitem.directive.js

@@ -42,7 +42,7 @@
                 item: '=',
                 onOpen: '&',
                 onOpenAnchor: '&',
-                index: '@'
+                hotkey: '<'
             }
         });
 

src/Umbraco.Web.UI.Client/src/views/components/editor/umb-editor-navigation-item.html

@@ -1,10 +1,10 @@
 <a data-element="sub-view-{{vm.item.alias}}"
-    tabindex="-1"
-    ng-href=""
-    ng-click="vm.clicked()"
-    hotkey="{{vm.index+1}}"
-    hotkey-when-hidden="true"
-    ng-class="{'is-active': vm.item.active, '-has-error': vm.item.hasError}">
+   tabindex="-1"
+   ng-href=""
+   ng-click="vm.clicked()"
+   hotkey="{{::vm.hotkey}}"
+   hotkey-when-hidden="true"
+   ng-class="{'is-active': vm.item.active, '-has-error': vm.item.hasError}">
     <i class="icon {{ vm.item.icon }}"></i>
     <span class="umb-sub-views-nav-item-text">{{ vm.item.name }}</span>
     <div ng-show="item.badge" class="badge -type-{{vm.item.badge.type}}">{{vm.item.badge.count}}</div>

src/Umbraco.Web.UI.Client/src/views/components/editor/umb-editor-navigation.html

@@ -7,7 +7,7 @@
                 item="navItem"
                 on-open="openNavigationItem(item)"
                 on-open-anchor="openAnchorItem(item, anchor)"
-                index="{{$index}}">
+                hotkey="$index + 1">
             </umb-editor-navigation-item>
         </div>
     </li>