fix flaky templates browser test (#5808)

Fixes flaky templates modal test introduced in
https://github.com/Comfy-Org/ComfyUI_frontend/pull/5802 by ensuring the
templates modal is visible before querying the visible card count and
asserting that it is greater than 0.

If we immediately count the number of cards after executing the "load
templates" command, it's possible that there are 0 visible due to them
loading (rather than being caused by a legitimate bug).

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5808-fix-flaky-templates-browser-test-27b6d73d365081e58c65f608944976a0)
by [Unito](https://www.unito.io)

browser_tests/tests/templates.spec.ts

@@ -181,6 +181,7 @@ test.describe('Templates', () => {
   }) => {
     // Open templates dialog
     await comfyPage.executeCommand('Comfy.BrowseTemplates')
+    await comfyPage.templates.content.waitFor({ state: 'visible' })
 
     const templateGrid = comfyPage.page.locator(
       '[data-testid="template-workflows-content"]'