Force Breathe extension for Sphinx to use the pyansys classes

### Description of the feature

I am not sure if this is the place to post this issue or not. I'll be pinging @jorgepiloto @Revathyvenugopal162 @akaszynski for discussion.

If you go to the following repository which uses the ``pyansys-sphinx-theme`` (https://github.com/ansys/api-eigen-example) you will see that in its docs, whatever has been rendered with the ``breathe`` extension (i.e. C++ code documentation compiled with ``Doxygen`` and reinterpreted with ``breathe``) has a different look&feel in comparison to the Python code docs.

A simple example may be seen by comparing these two sections:
* Normal case scenario: https://apieigen.docs.pyansys.com/api/python-grpc/server.html
* Breathe extension affected site: https://apieigen.docs.pyansys.com/api/cpp-rest/server.html

The goal is to have ``breathe`` use the same predefined classes of the ``pyansys-sphinx-theme`` so that the output has a similar look. This must probably be done via configuration of the ``breathe`` extension. Please, find the docs to the extension in the following site: https://breathe.readthedocs.io/en/latest/

### Steps for implementing the feature

Not known yet :) but it should be possible.

### Useful links and references

_No response_

Start by comparing the Python and C++ documentation pages linked in the issue, then read the Breathe extension configuration documentation and the pyansys-sphinx-theme styling behavior. Done means Breathe-rendered C++ documentation uses the theme's predefined classes and has a consistent look and feel with the Python documentation.

Written by the indexing model from the issue text.