Fix IsEnum check in cppyy/metacling

[aaronj0]

Fixes #10454, and the following reproducer no longer seg faults:

import ROOT

ROOT.gInterpreter.Declare('''
class UponCopyPrinter {
public:
   ~UponCopyPrinter() = default;          
   UponCopyPrinter() = default;      
   UponCopyPrinter(const UponCopyPrinter &) { std::cout << "Invoking copy c'tor!" << std::endl; }
   UponCopyPrinter(UponCopyPrinter &&) = default;
   UponCopyPrinter &operator=(const UponCopyPrinter &) = default;
   UponCopyPrinter &operator=(UponCopyPrinter &&) = default;
};
''')

RVec_UponCopyPrinter = ROOT.ROOT.VecOps.RVec(ROOT.UponCopyPrinter)

v = RVec_UponCopyPrinter(3)
v2 = RVec_UponCopyPrinter(v.data(), v.size())
print("%s and %s" %(v.data(), v2.data()))

v2.resize(4)
print("%s and %s" %(v.data(), v2.data()))

This PR also enables InterOp API in clingwrapper, which is the first step towards performing clang-based reflection in cppyy, bypassing the limitations of the type system.

I am currently testing in TCling whether this is ready to use for ClassInfo_IsEnum(expecting some failures). Ideally we would patch Cppyy::IsEnum to fix this issue, which I will test in a following commit after the CI run, hence the changes in clingwrapper's cmake.

cc @vepadulano

[github-actions]

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Results for commit 59ef22e.

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[hahnjo]

Note that by relying on CppInterOp will not allow to backport to 6.32 and 6.34 releases...

[pcanal]

Note: this solve the problem 'only' for Python. It would be even better to fix TCling::ClassInfo_IsEnum.

[aaronj0]

Agreed! The initial fix was in TCling(https://github.com/root-project/root/actions/runs/13424841558), that caused a certain set of test failures. I was curious to know which of them happened only via the python interface leading me to temporarily patch clingwrapper instead