Fix DNS2 self-updater path and sync live dashboard version UI

dashcaddy-api/__tests__/input-validator.test.js

@@ -14,6 +14,9 @@ const {
 } = require('../input-validator');
 
 describe('Input Validator', () => {
+  function fail(message) {
+    throw new Error(message);
+  }
 
   describe('ValidationError', () => {
     it('has correct name, message, field, and statusCode', () => {

dashcaddy-api/__tests__/routes/health.routes.test.js

@@ -524,9 +524,7 @@ describe('Health Routes', () => {
     it('returns error when no url parameter provided', async () => {
       const { app } = createApp();
       const res = await request(app).get('/api/health/probe');
-      // ValidationError is not imported at module scope, so this throws a ReferenceError
-      // which the error handler catches as a 500
-      expect(res.status).toBe(500);
+      expect(res.status).toBe(400);
     });
   });