open3d.cpu not found after successful py wheel build

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [x] For Python issues, I have tested with the [latest development wheel](https://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](https://www.open3d.org/docs/release/) and the [latest documentation](https://www.open3d.org/docs/latest/) (for `main` branch).

### Steps to reproduce the issue

#### I first cloned Open3D by:
```
git clone https://github.com/isl-org/Open3D.git
cd Open3D
```
#### Followed the docker to install dependencies for python and jupyter

#### Then, I build Open3D (on Ubuntu 22.04, with CUDA 11.8 and pytorch=2.1.2) with:
```
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_LIBREALSENSE=ON -DBUILD_CUDA_MODULE=ON -DBUILD_COMMON_ISPC_ISAS=ON -DCMAKE_CUDA_ARCHITECTURES="90;89;86;80" -DGLIBCXX_USE_CXX11_ABI=OFF -DBUILD_PYTORCH_OPS=ON -DBUNDLE_OPEN3D_ML=ON -DOPEN3D_ML_ROOT=/home/coelhomatias/Open3D-ML -DBUILD_UNIT_TESTS=ON -DBUILD_BENCHMARKS=ON -DBUILD_EXAMPLES=ON -DCMAKE_INSTALL_PREFIX=$HOME/open3d_install -DBUILD_WEBRTC=ON -DBUILD_JUPYTER_EXTENSION=ON ..
make -j$(nproc)
make pip-package -j$(nproc)
```
#### In another computer with a fresh install of Ubuntu22.04
- Create conda environment with miniconda
- Install correct pytorch version (2.1.2 for cu118)
- run `python -c "import open3d"`

### Error message

```shell
---------------------------------------------------------------------------
ModuleNotFoundError Traceback (most recent call last)
Cell In[2], line 1
----> 1 import open3d

File ~/fruitvista_open3d/.conda/lib/python3.11/site-packages/open3d/__init__.py:93
87 warnings.warn(
88 "Open3D was built with CUDA support, but Open3D CUDA Python "
89 "binding library not found! Falling back to the CPU Python "
90 "binding library.", ImportWarning)
92 if __DEVICE_API__ == "cpu":
---> 93 from open3d.cpu.pybind import (core, camera, data, geometry, io, pipelines,
94 utility, t)
95 from open3d.cpu import pybind
98 def _insert_pybind_names(skip_names=()):

ModuleNotFoundError: No module named 'open3d.cpu'
```

### Open3D, Python and System information

```markdown
- Operating system: Ubuntu 22.04 / macOS 10.15 / Windows 10 64-bit
- Python version: Python 3.11.7 (main, Dec 15 2023, 18:12:31) [GCC 11.2.0]
- Open3D version: 0.18
- System architecture: x86
- Is this a remote workstation?: WSL
- How did you install Open3D?: pip (after build wheel from source)
- Compiler version (if built from source): gcc 11.8 / clang 11.8
```

### Additional information

The presented error was actually the second encountered. The first error was related to libunwind.so.1.
This file was non existing even after `sudo apt-get install libunwind-dev`, however, a libunwind.so.8 existed and the error was "fixed" by doing a symbolic link between the files.