Refactor(eos_designs): Adjust class mixin layout and type hints

[ClausHolbechArista]

Change Summary

Related Issue(s)

Fixes #

Component(s) name

arista.avd.<role-name>

Proposed changes

How to test

Checklist

User Checklist

• N/A

Repository Checklist

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[github-actions]

Review docs on Read the Docs

To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4922
# Activate the virtual environment
source test-avd-pr-4922/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/ClausHolbechArista/avd.git@refactor/eos_designs/class-mixin-layout-and-type-hints#subdirectory=python-avd" --force
# Point Ansible collections path to the Python virtual environment
export ANSIBLE_COLLECTIONS_PATH=$VIRTUAL_ENV/ansible_collections
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/ClausHolbechArista/avd.git#/ansible_collections/arista/avd/,refactor/eos_designs/class-mixin-layout-and-type-hints --force
# Optional: Install AVD examples
cd test-avd-pr-4922
ansible-playbook arista.avd.install_examples

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.