Fix: Simplify the widget state logic (#6741)

## Summary

Fixes the case where a value is updated in the graph but the result
doesn't reflect on the widget representation on the relevant node.

## Changes

- **What**: Uses vanilla Vue utilities instead of a special utility
- **What**: Fewer places where state could be desynced.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6741-Fix-WIP-Simplify-the-widget-state-logic-2af6d73d36508160b729db50608a2ea9)
by [Unito](https://www.unito.io)

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Co-authored-by: github-actions <github-actions@github.com>

tests-ui/tests/renderer/extensions/vueNodes/widgets/components/WidgetSelect.asset-mode.test.ts

@@ -31,7 +31,7 @@ import { assetService } from '@/platform/assets/services/assetService'
 const mockAssetServiceEligible = vi.mocked(assetService.isAssetBrowserEligible)
 
 describe('WidgetSelect asset mode', () => {
-  const createWidget = (): SimplifiedWidget<string | number | undefined> => ({
+  const createWidget = (): SimplifiedWidget<string | undefined> => ({
     name: 'ckpt_name',
     type: 'combo',
     value: undefined,