pybind/pybind11: Version 3.0.3

Bug fixes: Fixed TSS key exhaustion in implicitly_convertible() when many implicit conversions are registered across large module sets. #6020 Fixed heap-buffer-overflow in pythonbuf with undersized buffers by enforcing a minimum buffer size. #6019 Fixed virtual-inheritance pointer offset crashes when dispatching inherited methods through virtual bases. #6017 Fixed free(): invalid pointer crashes during interpreter shutdown with py::enum_<> by duplicating late-added def_property_static argument strings. #6015 Fixed function_record heap-type deallocation to call PyObject_Free() and decref the type. #6010 Hardened PYBIND11_MODULE_PYINIT and get_internals() against module-initialization crashes. #6018 Fixed static_pointer_cast build failure with virtual inheritance in holder_caster_foreign_helpers.h. #6014 Fixed ambiguous factory template specialization that caused compilation failures with nvcc + GCC 14. #6011 Fixed crash in def_readwrite for non-smart-holder properties of smart-holder classes. #6008 Fixed memory leak for py::dynamic_attr() objects on Python 3.13+ by clearing managed __dict__ contents during deallocation. #5999 Fixed binding of noexcept and ref-qualified (&, &&) methods inherited from unregistered base classes. #5992 Internal: Moved tomlkit dependency to the dev dependency group. #5990 Switched to newer public CPython APIs (PyType_GetFlags and public vectorcall APIs where available). #6005 Tests: Made an async callback test deterministic by replacing fixed sleep with bounded waiting. #5986 CI: Re-enabled Android tests in the cibuildwheel workflow. #6001