Enforce the "Save and preview" button after when switching content app (#17985)

src/Umbraco.Web.UI.Client/src/common/directives/components/content/edit.controller.js

@@ -311,10 +311,12 @@
             // create the save button
             if (_.contains($scope.content.allowedActions, "A")) {
                 $scope.page.showSaveButton = true;
+                $scope.page.showPreviewButton = true;
                 // add ellipsis to the save button if it opens the variant overlay
                 $scope.page.saveButtonEllipsis = content.variants && content.variants.length > 1 ? "true" : "false";
             } else {
                 $scope.page.showSaveButton = false;
+                $scope.page.showPreviewButton = false;
             }
 
             // create the pubish combo button