fix(cloud): disable legacy node templates feature on cloud (#8462)

## Summary

Disables the legacy "node templates" feature on ComfyUI Cloud. This
feature is accessed via right-clicking on the canvas and is distinct
from both subgraphs and workflow templates.

## Problem

The legacy node templates feature presents false-positive errors on
cloud:
- Errors appear when no existing templates exist initially
- After refresh, workflow progress is lost from workflow tabs
- Node templates fail to delete (except the first one)

## Solution

Conditionally load the `nodeTemplates` extension only for non-cloud
builds by wrapping the import in `if (!isCloud)`.

## Testing

- [ ] Verify right-click canvas menu no longer shows "Node Templates"
submenu on cloud
- [ ] Verify right-click canvas menu no longer shows "Save Selected as
Template" on cloud
- [ ] Verify the feature still works on desktop/OSS builds

## Related

- Refs: COM-14105
- Related issue: #4056 (Migrate Node Templates to Workflows)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8462-fix-cloud-disable-legacy-node-templates-feature-on-cloud-2f86d73d36508162948cc897d4c7ef5e)
by [Unito](https://www.unito.io)

Co-authored-by: Amp <amp@ampcode.com>

src/extensions/core/index.ts

@@ -13,7 +13,9 @@ import './imageCompare'
 import './imageCrop'
 import './load3d'
 import './maskeditor'
-import './nodeTemplates'
+if (!isCloud) {
+  await import('./nodeTemplates')
+}
 import './noteNode'
 import './previewAny'
 import './rerouteNode'