Fix Clang-Format workflow failure caused by shallow checkout state

[Copilot]

The Clang-Format Actions job failed while creating the formatting PR, not during formatting, due to a shallow-repo fetch transition (git fetch --unshallow) error. This change ensures the workflow starts from a full clone so downstream git operations are stable.

• Workflow hardening

  • Updated .github/workflows/native-clang-format.yml checkout step to fetch full history (fetch-depth: 0) for the PR head SHA used by the formatting job.
  • Prevents the fatal: shallow file has changed since we read it failure path in later branch/reset logic.

• Minimal diff

  • Single-line workflow change; no formatting logic, paths, or exclusions were modified.

- uses: actions/checkout@v4
  with:
    token: ${{ github.token }}
    ref: ${{ github.head_sha }}
    fetch-depth: 0

测试方法

不需要测试，用于github cocos robot提交clang format代码。