test: fix test and remove the broken url

Author: hamed-musallam

src/demo/NMRiumWrapperDemo.tsx

@@ -45,7 +45,6 @@ export default function NMRiumWrapperDemo() {
                 'https://cheminfo.github.io/nmr-dataset-demo/cytisine/13c.jdx',
                 'https://cheminfo.github.io/nmr-dataset-demo/cytisine/1h.jdx',
                 'https://cheminfo.github.io/bruker-data-test/data/zipped/aspirin-1h.zip',
-                'https://nmrxiv.org/NRayya/datasets/fsu-nmr-platform-samples/cucurbitacin-e/12',
                 '../data/13c.zip',
               ],
               type: 'url',

test-e2e/core.test.ts

@@ -23,6 +23,8 @@ test('should load NMRium from external Urls', async ({ page }) => {
 
   await nmrium.page.click('text=Test Load from URLS');
 
+  await page.locator('text=Loading').waitFor({ state: 'hidden' });
+
   // if loaded successfully, there should be a 1H and 13C tabs
   await test.step('spectra should be loaded', async () => {
     await expect(