test(core): enable no-floating-promises rule for tests (#11915)

Sometimes, missing `await` in the test code can cause timing issues, leading to test failures. This PR enables the `no-floating-promises` rule for the test code to ensure that such errors do not occur.

tests/affine-local/e2e/blocksuite/list.spec.ts

@@ -48,7 +48,7 @@ test.describe('split list', () => {
       listLocator.nth(2).locator('.affine-list-block__numbered')
     ).toHaveText('2.');
     await expect(listLocator.nth(3).locator('rich-text')).toHaveText('ddd');
-    expect(
+    await expect(
       listLocator.nth(3).locator('.affine-list-block__numbered')
     ).toHaveText('3.');