node: Clear router IPs on Uninitialize()
node: Clear router IPs on Uninitialize()

The subsequent commit will add unit tests that make use of
ipv{4,6}RouterAddress and state will need to be cleared during testing.

Signed-off-by: Chris Tarazi <711c73f64afdce07b7e38039a96d2224209e9a6c@isovalent.com>

michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium