ci: pin cpplint reviewdog action

[zcxGGmu]

Summary

• Pin reviewdog/action-cpplint to a full commit SHA instead of the mutable master branch.
• Keep the existing lint-cpp step configuration unchanged.

Fixes #29710

Test Plan

• python check that reviewdog/action-cpplint@master is removed and the action is pinned to a 40-character SHA
• python YAML parse check that the cpplint step and github_token configuration are unchanged apart from the action ref
• git diff --check
• diff secret/conflict scan (github_token line is unchanged and expected)

[azure-pipelines]

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