fix(test): import AppMode from utils/appMode in WorkflowHelper (#13003)

## Summary

`pnpm typecheck:browser` (`vue-tsc --project
browser_tests/tsconfig.json`) currently fails on `main`, turning
`lint-and-format` red for every PR built on it:

```
browser_tests/fixtures/helpers/WorkflowHelper.ts(5,15): error TS2459:
Module '"@/composables/useAppMode"' declares 'AppMode' locally, but it is not exported.
```

## Cause

#12925 (`bc885f383c`, "Decouple run telemetry context from providers")
moved the `AppMode` type from `@/composables/useAppMode` to
`@/utils/appMode`. `useAppMode` now only `import type`s `AppMode` (it no
longer re-exports it), so this fixture's `import type { AppMode } from
'@/composables/useAppMode'` became invalid. The other `useAppMode`
import sites are unaffected — they import the `useAppMode` composable
(still exported), not the type.

## Fix

Import `AppMode` from its actual source, `@/utils/appMode`. One line, no
behavior change.

Verified `vue-tsc --project browser_tests/tsconfig.json` no longer
reports the `WorkflowHelper.ts` error.

browser_tests/fixtures/helpers/TemplateHelper.ts

@@ -69,24 +69,6 @@ export class TemplateHelper {
   }
 
   async mockIndex(): Promise<void> {
-    const customTemplatesHandler = async (route: Route) => {
-      const customTemplates: Record<string, string[]> = {}
-      await route.fulfill({
-        status: 200,
-        body: JSON.stringify(customTemplates),
-        headers: {
-          'Content-Type': 'application/json',
-          'Cache-Control': 'no-store'
-        }
-      })
-    }
-    const customTemplatesPattern = '**/api/workflow_templates'
-    this.routeHandlers.push({
-      pattern: customTemplatesPattern,
-      handler: customTemplatesHandler
-    })
-    await this.page.route(customTemplatesPattern, customTemplatesHandler)
-
     const indexHandler = async (route: Route) => {
       const payload = this.index ?? mockTemplateIndex(this.templates)
       await route.fulfill({

browser_tests/tests/templateFilteringCount.spec.ts

@@ -1,13 +1,13 @@
 import { expect, mergeTests } from '@playwright/test'
 
 import { TemplateIncludeOnDistributionEnum } from '@/platform/workflow/templates/types/template'
-import { createCloudAssetsFixture } from '@e2e/fixtures/assetApiFixture'
+import { comfyPageFixture } from '@e2e/fixtures/ComfyPage'
 import { makeTemplate } from '@e2e/fixtures/data/templateFixtures'
 import { withTemplates } from '@e2e/fixtures/helpers/TemplateHelper'
 import { TestIds } from '@e2e/fixtures/selectors'
 import { templateApiFixture } from '@e2e/fixtures/templateApiFixture'
 
-const test = mergeTests(createCloudAssetsFixture([]), templateApiFixture)
+const test = mergeTests(comfyPageFixture, templateApiFixture)
 
 const Cloud = TemplateIncludeOnDistributionEnum.Cloud
 const Desktop = TemplateIncludeOnDistributionEnum.Desktop