fix(ci): globally install @cctest/scheduler in Windows test jobs

[Copilot]

The Win-RunTestCases and Win-RunTestCasesCustom jobs were failing because the scheduler CLI (@cctest/scheduler) was not available in PowerShell's PATH — the npm install step only installs local project dependencies, leaving the global binary absent.

Changes

• .github/workflows/run_test_cases.yml: added npm install -g @cctest/scheduler to the npm install step in both Windows jobs (Win-RunTestCases and Win-RunTestCasesCustom), using the same mirror registry already in use:

- name: npm install
  run: |
    npm -v
    npm install --registry https://registry.npmmirror.com
    npm install -g @cctest/scheduler --registry https://registry.npmmirror.com

This places the scheduler binary on the global PATH before the "Run test cases" step executes, and also ensures the expected global module path (%APPDATA%\npm\node_modules\@cctest\scheduler\...) exists for the job-ID read that follows.

[star-e]

@cocos-robot run test cases

[github-actions]

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