[perf] disable cache-busting param on cloud (#6105)

## Summary

Updates `ComfyApp.getRandParam()` to return an empty string on cloud
builds (detected via `isCloud`), letting hosted deployments rely on HTTP
caching for `/view` assets while local hosts retain the legacy cache
busting. The audio widget helpers now defer to the same method instead
of generating their own random suffix, so every frontend consumer shares
this logic.

This keeps the original overwrite protection for localhost workflows but
removes needless cache misses in the cloud stack, where GCS already
serve strong ETags and there is not really a concern about stale
filenames. Once the backend exposes a deterministic file-version field,
we can delete the remaining local-only randomness entirely.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6105-perf-disable-cache-busting-param-on-cloud-28f6d73d36508181b34afad406fabc59)
by [Unito](https://www.unito.io)

src/scripts/app.ts

@@ -16,6 +16,7 @@ import {
 } from '@/lib/litegraph/src/litegraph'
 import type { Vector2 } from '@/lib/litegraph/src/litegraph'
 import type { IBaseWidget } from '@/lib/litegraph/src/types/widgets'
+import { isCloud } from '@/platform/distribution/types'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { useToastStore } from '@/platform/updates/common/toastStore'
 import { useWorkflowService } from '@/platform/workflow/core/services/workflowService'
@@ -336,6 +337,7 @@ export class ComfyApp {
   }
 
   getRandParam() {
+    if (isCloud) return ''
     return '&rand=' + Math.random()
   }