[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/i18n-custom-nodes.yaml

@@ -22,13 +22,13 @@ jobs:
     runs-on: ubuntu-latest
     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
@@ -37,7 +37,7 @@ jobs:
         mkdir -p ComfyUI/custom_nodes/ComfyUI_devtools
         cp -r ComfyUI_frontend/tools/devtools/* ComfyUI/custom_nodes/ComfyUI_devtools/
     - name: Checkout custom node repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v5
       with:
         repository: ${{ inputs.owner }}/${{ inputs.repository }}
         path: 'ComfyUI/custom_nodes/${{ inputs.repository }}'