[clang] [analyzer] Prevent triplicate warnings for `sarif-html` (PR #158112)

[Balazs Benics via cfe-commits]

https://github.com/steakhal approved this pull request.

> Can we have a test case for plist-html as well? Otherwise LGTM!

+1

https://github.com/llvm/llvm-project/pull/158112