Fix vxlan cross-subnet routes in pure V6 env

[tomastigera]

In a pure V6 env, nodes do not have v4 addresses and thus testing localNodeInfo.V4CIDR.ContainsV4(nodeInfo.V4Addr) is always true and sameV4 || sameV6 would also always evaluate to true.

It is better to evaluate nodeInOurSubnet separately for each IP family.

fixes https://github.com/projectcalico/calico/issues/9403

Description

Related issues/PRs

Todos

• [x] Tests
• [ ] Documentation
• [x] Release note

Release Note

Fix missing routes when vxlan mode is cross-subnet and the environment is purely V6 (no V4 host addresses)

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