[llvm] [Github][libc++] Bump Ubuntu ver back to 26.04 and remove clang-format for Generated Files check (PR #226219)

[Aiden Grossman via llvm-commits]

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@@ -25,7 +20,7 @@ jobs:
       - name: Install dependencies
         uses: aminya/setup-cpp at 8170d66c458f4a045220b7b0966c10940bb2a15d # v1.8.1
         with:
-          clangformat: 17.0.1
+          clangformat: 23.1.0
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boomanaiden154 wrote:

The failing tests don't have anything to do with this PR. As I mentioned above we can also drop the entirety of the `Install dependencies` step, not just the `clang-format` installation.

https://github.com/llvm/llvm-project/pull/226219