fix(e2e): Race condition in dialog modal test (#12554)

The race condition on the test is happening because, we are immediately
calling `page.goto()` after the `Commit changes` button is clicked
without waiting for the previous redirect to finish. This interruption leads
to the error: `Error: page.goto: Target page, context or browser has been
closed`.

By adding the `await expect(page).toHaveURL`, Playwright waits for the
redirection and verifies the URL and then finally go to the next `await
page.goto()` to go to the `edit` page of the file.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12554
Reviewed-by: Gusted <gusted@noreply.codeberg.org>

tests/e2e/modal.test.e2e.ts

@@ -28,6 +28,7 @@ test('Dialog modal', async ({page}) => {
 
   await page.locator('.quick-pull-choice input[value="direct"]').click();
   await page.getByRole('button', {name: 'Commit changes'}).click();
+  await expect(page).toHaveURL(`/user2/repo1/src/branch/master/${filename}`);
 
   response = await page.goto(`/user2/repo1/_edit/master/${filename}`, {waitUntil: 'domcontentloaded'});
   expect(response?.status()).toBe(200);