Fix(eos_designs): Empty description under network-ports

[gmuloc]

Change Summary

Strip empty strings from the rendered structured_config for ethernet_interfaces for connected_endpoints

Related Issue(s)

Fixes #3443

Component(s) name

arista.avd.eos_designs

Proposed changes

Replacing the default tuple for strip_null_fom_data with (None, "").
Apply same fix for port-channels where the issue can also be reproduced

How to test

molecule (first commit shows the issue)

Checklist

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)

[bjmeuer]

Tested with:

network_ports:
  - switches:
      - dee-lf93101[a,b]
    switch_ports:
      - Ethernet1-24/1-4

works fine for me