Doc: Added the table of WAN validation

[MaheshGSLAB]

Change Summary

Added the table of WAN validation.

Component(s) name

AVD Documentation

Proposed changes

Added the table of WAN validation to WAN How-To guide

Repository Checklist

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

[github-actions[bot]]

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To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4125
# Activate the virtual environment
source test-avd-pr-4125/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/MaheshGSLAB/ansible-avd.git@WAN-test-doc#subdirectory=python-avd" --force
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/MaheshGSLAB/ansible-avd.git#/ansible_collections/arista/avd/,WAN-test-doc --force
# Optional: Install AVD examples
cd test-avd-pr-4125
ansible-playbook arista.avd.install_examples