fixed #14084 - run CMake with `--warn-uninitialized` in CI #558

Job	Run time
iwyu (ubuntu-22.04, fedora:rawhide, libc++)	8m 58s
iwyu (macos-26, libc++, -Xiwyu --mapping_file=$(realpath ./macos.imp))	4m 11s
iwyu (ubuntu-22.04, fedora:rawhide, libstdc++)	6m 58s
clang-include-cleaner (libc++)	10m 27s
clang-include-cleaner (libstdc++)	8m 22s
	38m 56s

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