[clang-tools-extra] [clang-tidy] Fix invalid fixit from modernize-use-ranges for nullptr used with std::unique_ptr (PR #127162)

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chrchr-github wrote:

Thanks for addressing this. However I think a more general solution is required (instead of special-casing `std::unique_ptr`/`nullptr`), see https://github.com/llvm/llvm-project/issues/124815#issuecomment-2676753012

https://github.com/llvm/llvm-project/pull/127162