Getting custom layer data crashes Maya

### Description of Issue
Getting the custom layer data from a layer created in Autodesk Bifrost raises an error.

---

### Steps to Reproduce
1. Create a simple layer like in the following image

2. Try to query the custom layer data from USD, it causes Maya to crash:
```py
from pxr import Sdf

identifier = "anon:0x7f6b8c051af0:bifrost.usd" # put here whatever the identifier is
layer = Sdf.Layer.FindOrOpen(identifier)
layer.customLayerData
```

---

### Stack Trace
```js
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Vt/_vt.so(+0x9cc871) [0x7f2c24dcc871]
boost::python::converter::detail::arg_to_python_base::arg_to_python_base(void const volatile*, boost::python::converter::registration const&)
boost::python::api::object pxrInternal_v0_22__pxrReserved__::TfPyObject(pxrInternal_v0_22__pxrReserved__::VtValue const&, bool)
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Vt/_vt.so(+0x9c62d2) [0x7f2c24dc62d2]
boost::python::objects::caller_py_function_impl > >::operator()(_object*, _object*)
boost::python::objects::function::call(_object*, _object*) const
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Tf/../../../libboost_python310.so.1.76.0(+0x1fcf6) [0x7f2c326accf6]
boost::python::detail::exception_handler::operator()(boost::function0 const&) const
boost::detail::function::function_obj_invoker2, boost::_bi::list3, boost::arg<2>, boost::_bi::value > >, bool, boost::python::detail::exception_handler const&, boost::function0 const&>::invoke(boost::detail::function::function_buffer&, boost::python::detail::exception_handler const&, boost::function0 const&)
boost::python::handle_exception_impl(boost::function0)
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Tf/../../../libboost_python310.so.1.76.0(+0x1d722) [0x7f2c326aa722]
_PyObject_Call
boost::python::objects::full_py_function_impl >::operator()(_object*, _object*)
boost::python::objects::function::call(_object*, _object*) const
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Tf/../../../libboost_python310.so.1.76.0(+0x1fcf6) [0x7f2c326accf6]
boost::python::detail::exception_handler::operator()(boost::function0 const&) const
boost::detail::function::function_obj_invoker2, boost::_bi::list3, boost::arg<2>, boost::_bi::value > >, bool, boost::python::detail::exception_handler const&, boost::function0 const&>::invoke(boost::detail::function::function_buffer&, boost::python::detail::exception_handler const&, boost::function0 const&)
boost::python::handle_exception_impl(boost::function0)
/usr/autodesk/mayausd/maya2024/0.29.0_202406120659-f8eb6c1/mayausd/USD/lib/python/pxr/Tf/../../../libboost_python310.so.1.76.0(+0x1d722) [0x7f2c326aa722]
_PyObject_MakeTpCall
/usr/autodesk/maya2024/lib/libpython3.10.so.1.0(+0xcd540) [0x7f2c786cd540]
_PyObject_GenericGetAttrWithDict
PyObject_GetAttr
_PyEval_EvalFrameDefault
/usr/autodesk/maya2024/lib/libpython3.10.so.1.0(+0x1bda24) [0x7f2c787bda24]
PyEval_EvalCode
TpythonInterpreter::executeCommand(Tstring const&, bool, bool, TinterpreterResult*)
/usr/autodesk/maya2024/lib/libExtensionLayer.so(+0x36985a) [0x7f2c8556985a]
TidleAction::preDoIdleAction(Tevent const&)
/usr/autodesk/maya2024/lib/libExtensionLayer.so(+0x2fbcf7) [0x7f2c854fbcf7]
TeventHandler::doIdles()
/usr/autodesk/maya2024/lib/libExtensionLayer.so(+0x317155) [0x7f2c85517155]
QObject::event(QEvent*)
QApplicationPrivate::notify_helper(QObject*, QEvent*)
/usr/autodesk/maya2024/lib/libExtensionLayer.so(+0x3040bd) [0x7f2c855040bd]
QCoreApplication::notifyInternal2(QObject*, QEvent*)
QTimerInfoList::activateTimers()
/usr/autodesk/maya2024/lib/libQt5Core.so.5(+0x300564) [0x7f2c81d00564]
g_main_context_dispatch
/lib64/libglib-2.0.so.0(+0xa9508) [0x7f2c7796f508]
```

---

### System Information
Maya version: 2024.2
Bifrost version: 2.10.0.0
Maya USD version: 0.29.0

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Related to https://github.com/PixarAnimationStudios/OpenUSD/issues/3202