Fix cilium strict kube proxy replacement in HA (#6473)

* Update the cilium svc proxy test to HA mode

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>

* Fix cilium strict kube-proxy in HA

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>

* Add a single global endpoint variable

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>

* Add cilium docs about kube-proxy replacement

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>

* Fix issues in docs

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>