Fix(eos_designs)!: Prevent configuration of IP routing on l2leaf

[ClausHolbechArista]

Change Summary

Prevent configuration of IP routing on l2leaf

Related Issue(s)

Fixes #1988

Component(s) name

arista.avd.eos_designs

Proposed changes

IP and IPv6 routing is no longer configured on pure L2 devices

For node types like l2leaf where underlay_router is set to false under node_type_keys AVD versions below 4.0.0
still rendered ip routing, ip routing ipv6 interfaces and/or ipv6 unicast-routing in the configuration.
As of AVD version 4.0.0 these IP and IPv6 routing configurations are no longer configured for l2leaf
or other node types with underlay_router: false.

To retain the old behavior the inventory can be updated like this:

l2leaf:
  defaults:
    always_configure_ip_routing: true

How to test

Most molecule scenarios remove the config, but I have added a unit test combined with rfc5549 and also set always_configure_ip_routing on the spines in the eos_designs-l2ls scenario to test with ipv4 (IMO not worth another host in unit tests).

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)

[carlbuchmann]

LGTM