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/kit/src/utils/editor.ts

@@ -473,7 +473,7 @@ export async function createEdgelessNoteBlock(
 ) {
   await setEdgelessTool(page, 'note', undefined, editorIndex);
   if (position.length === 4) {
-    dragView(
+    await dragView(
       page,
       [position[0], position[1]],
       [position[0] + position[2], position[1] + position[3]]

tests/kit/src/utils/properties.ts

@@ -122,7 +122,7 @@ export const addCustomProperty = async (
   root: Locator | Page,
   type: string
 ) => {
-  ensureAddPropertyButtonVisible(page, root);
+  await ensureAddPropertyButtonVisible(page, root);
   await clickAddPropertyButton(root);
   await page
     .locator(