[BUILD] nanovdb/util/cuda in NanoVDB 11 installs to invalid folder

### Environment
**Operating System: Windows 10**
**Version nanoVDB 11 / Commit SHA: 77f28d16114949dfbe2937aa2dae1379f6d2b653**
**CMake Version: 3.27.7**
**Compiler:MSVC 2022**

### Describe the problem
[The release notes](https://www.openvdb.org/documentation/doxygen/changes.html#:~:text=by%C2%A0Matthias%C2%A0Ueberheide%5D-,NanoVDB,-%3A) state that the CUDA-related headers for NanoVDB have been added to nanovdb/util/cuda, but due to an incorrect CMake script, they are actually installed under nanovdb/util.
This causes projects that use NanoVDB as a library to fail to build when including header files under nanovdb/util/cuda, which destroys the relative reference to nanovdb/util.

### To Reproduce
Steps to reproduce the behavior:
1. Checkout repo 'master'
2. Run CMake and Build
```PowerShell
cmake -S . -B .\build -DCMAKE_INSTALL_PREFIX=D:\openvdb\build\Release -DOPENVDB_BUILD_BINARIES=OFF -DUSE_AX=OFF -DUSE_NANOVDB=ON -DOPENVDB_BUILD_NANOVDB=ON -DNANOVDB_BUILD_TOOLS=OFF -DNANOVDB_USE_CUDA=ON -DCMAKE_TOOLCHAIN_FILE='C:\Program Files\Microsoft Visual Studio\2022\Community\VC\vcpkg\scripts\buildsystems\vcpkg.cmake' -DVCPKG_TARGET_TRIPLET=x64-windows -A x64`
cmake --build .\build --parallel 8 --config Release --target install
```
3. Goto `.\build\Release\include\nanovdb\util` and check directory structure

Reproduce the Windows installation with the provided CMake configure and build commands, then inspect the CMake install rules responsible for NanoVDB headers under nanovdb/util/cuda. Done means the CUDA-related headers install under nanovdb/util/cuda so projects including those paths build successfully.

Written by the indexing model from the issue text.