Fix sycl::queue leak in usm_ndarray get_queue()/get_device()

[vlad-perevezentsev]

This PR fixes a memory leak in the C++ accessors usm_ndarray::get_queue() and get_device() in dpnp/include/dpnp4pybind11.hpp

UsmNDArray_GetQueueRef_ (dpnp's usm_ndarray.get_queue_ref()) returns an owning copy of the queue (it calls DPCTLQueue_Copy i.e. new sycl::queue)
Both accessors dereferenced this pointer and copied the queue out but never freed the heap copy, leaking one sycl::queue per call. Under queue churn this keeps queue_impl alive and prevents reuse of the associated Level Zero command lists / event pools.

The fix takes ownership of the returned copy with std::unique_ptr<sycl::queue>.
dpctl needs no change because its Memory_GetQueueRef returns a borrowed ref, whereas dpnp's UsmNDArray_GetQueueRef is documented to return a copy so it must be deleted.

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