[ci] Upgrade actions/checkout from v4 to v5 (#5859)

## Summary
- Upgrades all GitHub Actions workflows to use `actions/checkout@v5` 
- Updates 33 instances across 17 workflow files
- Ensures we're using the latest version with security patches and
improvements

## Changes
Updated the following workflow files from `actions/checkout@v4` to
`actions/checkout@v5`:
- `.github/workflows/backport.yaml`
- `.github/workflows/chromatic.yaml`
- `.github/workflows/claude-pr-review.yml`
- `.github/workflows/create-release-candidate-branch.yaml`
- `.github/workflows/dev-release.yaml`
- `.github/workflows/devtools-python.yaml`
- `.github/workflows/i18n-custom-nodes.yaml`
- `.github/workflows/json-validate.yaml`
- `.github/workflows/lint-and-format.yaml`
- `.github/workflows/pr-playwright-deploy.yaml`
- `.github/workflows/pr-storybook-deploy.yaml`
- `.github/workflows/test-ui.yaml`
- `.github/workflows/update-electron-types.yaml`
- `.github/workflows/update-manager-types.yaml`
- `.github/workflows/update-registry-types.yaml`
- `.github/workflows/version-bump.yaml`
- `.github/workflows/vitest.yaml`

Note: `.github/workflows/publish-frontend-types.yaml` and
`.github/workflows/release.yaml` were already using v5.

## Test plan
- [ ] CI workflows should continue to run successfully
- [ ] No functional changes - this is a dependency version upgrade only

🤖 Generated with [Claude Code](https://claude.ai/code)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5859-ci-Upgrade-actions-checkout-from-v4-to-v5-27e6d73d3650815488adee20c74c0464)
by [Unito](https://www.unito.io)

Co-authored-by: Claude <noreply@anthropic.com>

.github/workflows/test-ui.yaml

@@ -15,14 +15,14 @@ jobs:
       playwright-version: ${{ steps.playwright-version.outputs.PLAYWRIGHT_VERSION }}
     steps:
       - name: Checkout ComfyUI
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           repository: 'comfyanonymous/ComfyUI'
           path: 'ComfyUI'
           ref: master
 
       - name: Checkout ComfyUI_frontend
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           repository: 'Comfy-Org/ComfyUI_frontend'
           path: 'ComfyUI_frontend'
@@ -250,7 +250,7 @@ jobs:
     if: ${{ !cancelled() }}
     steps:
       - name: Checkout ComfyUI_frontend
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           repository: 'Comfy-Org/ComfyUI_frontend'
           path: 'ComfyUI_frontend'
@@ -306,7 +306,7 @@ jobs:
       pull-requests: write
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         
       - name: Get start time
         id: start-time
@@ -333,7 +333,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         
       - name: Download all playwright reports
         uses: actions/download-artifact@v4