fix: Don't strip 'app' from doctype route names

After creation of a new document and going back would break routes for doctypes that start with 'App'. In observed instance, it would clips the “app” portion in the appraisal and appraisal-template.

frappe/public/js/frappe/router.js

@@ -372,7 +372,8 @@ frappe.router = {
 
 	strip_prefix(route) {
 		if (route.substr(0, 1)=='/') route = route.substr(1); // for /app/sub
-		if (route.startsWith('app')) route = route.substr(4); // for desk/sub
+		if (route.startsWith('app/')) route = route.substr(4); // for desk/sub
+		if (route == 'app') route = route.substr(4); // for /app
 		if (route.substr(0, 1)=='/') route = route.substr(1);
 		if (route.substr(0, 1)=='#') route = route.substr(1);
 		if (route.substr(0, 1)=='!') route = route.substr(1);