Pip install mavproxy fails with missing attrdict

Mac OS 13.4
Python 3.11.3
pip 23.0.1

Apparently we're missing a transitive dependency on `attrdict3` via `wxPython`

```
pip install mavproxy
Collecting mavproxy
Using cached MAVProxy-1.8.60.tar.gz (9.4 MB)
Preparing metadata (setup.py) ... done
Collecting pymavlink>=2.4.14
Using cached pymavlink-2.4.38-py3-none-any.whl (11.3 MB)
Collecting pyserial>=3.0
Using cached pyserial-3.5-py2.py3-none-any.whl (90 kB)
Collecting numpy
Using cached numpy-1.24.3-cp311-cp311-macosx_11_0_arm64.whl (13.8 MB)
Collecting billiard>=3.5.0
Using cached billiard-4.1.0-py3-none-any.whl (86 kB)
Collecting gnureadline
Using cached gnureadline-8.1.2-cp311-cp311-macosx_11_0_arm64.whl (149 kB)
Collecting matplotlib
Using cached matplotlib-3.7.1-cp311-cp311-macosx_11_0_arm64.whl (7.3 MB)
Collecting opencv-python
Using cached opencv_python-4.7.0.72-cp37-abi3-macosx_11_0_arm64.whl (32.6 MB)
Collecting lxml
Using cached lxml-4.9.2-cp311-cp311-macosx_13_0_arm64.whl
Requirement already satisfied: future in ./venv/lib/python3.11/site-packages (from mavproxy) (0.18.3)
Collecting wxPython
Using cached wxPython-4.2.0.tar.gz (71.0 MB)
Preparing metadata (setup.py) ... error
error: subprocess-exited-with-error

× python setup.py egg_info did not run successfully.
│ exit code: 1
╰─> [8 lines of output]
Traceback (most recent call last):
File "", line 2, in
File "", line 34, in
File "/private/var/folders/5z/m09m46753_n3thjhdlhnjrpm0000gp/T/pip-install-t1o5wr8r/wxpython_5aecb8bf042348c5b8223bc915d5c476/setup.py", line 27, in
from buildtools.config import Config, msg, opj, runcmd, canGetSOName, getSOName
File "/private/var/folders/5z/m09m46753_n3thjhdlhnjrpm0000gp/T/pip-install-t1o5wr8r/wxpython_5aecb8bf042348c5b8223bc915d5c476/buildtools/config.py", line 30, in
from attrdict import AttrDict
ModuleNotFoundError: No module named 'attrdict'
[end of output]
```

Start by reproducing `pip install mavproxy` with the Python, pip, and macOS versions in the report, then inspect MAVProxy's packaging dependency declarations and the wxPython `setup.py`/`buildtools/config.py` locations named in the traceback. Done means installation completes without the missing `attrdict` error on the reported environment.

Written by the indexing model from the issue text.