[DF] Compilation failure when a mutable lambda is passed to Foreach #8317
Description
To Reproduce
#include <ROOT/RDataFrame.hxx>
int main() {
int i = 0;
ROOT::RDataFrame(10).Foreach([&](ULong64_t e) mutable { ++i; }, {"rdfentry_"});
return i;
}Currently this fails to compile because the helper type AddSlotParameter expects a const functor.