Build error for the tests with clang 19

[emmenlau]

In our build system, I'm getting the following error when building the tests for boost 1.87.0 using clang 19.1.7:

    "clang++"   -std=c++20 -pthread -O3 -fno-inline -Wall -g -m64 --target=x86_64-pc-linux    -DDEBUG  -fdebug-prefix-map=/data/bdaci01/BioDataAnalysis/ci-tmp-U2404Sk64c191/Debug/boost=/home/bdaci01/builds/6b652442/0/BioDataAnalysis/boost    -DDEBUG      -march=skylake -std=gnu++20     -O0 -glldb     -fno-omit-frame-pointer     -ftemplate-backtrace-limit=40     -ftime-trace -pedantic -Wextra -Wsign-compare -Wstrict-aliasing -fstrict-aliasing -Wvexing-parse -Wfloat-conversion -fvisibility=hidden -fvisibility-inlines-hidden    -DDEBUG  -fdebug-prefix-map=/data/bdaci01/BioDataAnalysis/ci-tmp-U2404Sk64c191/Debug/boost=/home/bdaci01/builds/6b652442/0/BioDataAnalysis/boost    -DDEBUG  -march=skylake     -O0 -glldb     -fno-omit-frame-pointer     -ftemplate-backtrace-limit=40     -ftime-trace -DBOOST_ALL_NO_LIB=1 -DBOOST_COBALT_USE_STD_PMR=1   -I".." -I"/data/bdaci01/BioDataAnalysis/ci-dst-U2404Sk64c191/Debug/include" -I"/data/bdaci01/BioDataAnalysis/ci-dst-U2404Sk64c191/Extras/include" -I"/data/bdaci01/BioDataAnalysis/ci-tmp-U2404Sk64c191/Debug/boost"  -c -o "../bin.v2/libs/histogram/test/algorithm_empty_test.test/clang-linux-19/debug/x86_64/cxxstd-20-iso/link-static/optimization-speed/pch-off/threading-multi/algorithm_empty_test.o" "../libs/histogram/test/algorithm_empty_test.cpp"

In file included from ../libs/histogram/test/algorithm_empty_test.cpp:14:
In file included from ../libs/histogram/test/histogram.hpp:15:
In file included from ../boost/histogram/make_histogram.hpp:17:
In file included from ../boost/histogram/histogram.hpp:15:
../boost/histogram/detail/fill.hpp:48:7: error: static assertion failed due to requirement 'std::is_convertible<std::tuple<int>, std::tuple<const double &>>::value': error: sample argument(s) not convertible to accumulator argument(s)
   48 |       std::is_convertible<std::tuple<Passed...>, std::tuple<Expected...>>::value,
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../boost/histogram/histogram.hpp:204:5: note: in instantiation of template class 'boost::histogram::detail::sample_args_passed_vs_expected<std::tuple<int>, std::tuple<const double &>>' requested here
  204 |     detail::sample_args_passed_vs_expected<typename arg_traits::sargs,
      |     ^
../boost/histogram/histogram.hpp:193:12: note: in instantiation of function template specialization 'boost::histogram::histogram<std::tuple<boost::histogram::axis::integer<>, boost::histogram::axis::integer<>>, boost::histogram::storage_adaptor<std::vector<boost::histogram::accumulators::weighted_mean<>>>>::operator()<const boost::histogram::weight_type<int> &, const int &, const int &, const boost::histogram::sample_type<std::tuple<int>> &>' requested here
  193 |     return operator()(std::forward_as_tuple(arg0, args...));
      |            ^
../libs/histogram/test/algorithm_empty_test.cpp:46:5: note: in instantiation of function template specialization 'boost::histogram::histogram<std::tuple<boost::histogram::axis::integer<>, boost::histogram::axis::integer<>>, boost::histogram::storage_adaptor<std::vector<boost::histogram::accumulators::weighted_mean<>>>>::operator()<boost::histogram::weight_type<int>, int, int, boost::histogram::sample_type<std::tuple<int>>, void>' requested here
   46 |     h(weight(2), -2, -4, sample(3));
      |     ^
../libs/histogram/test/algorithm_empty_test.cpp:61:3: note: in instantiation of function template specialization 'run_tests<boost::histogram::static_tag>' requested here
   61 |   run_tests<static_tag>();
      |   ^
1 error generated.