policy: Fix ChangeUser add/remove order
policy: Fix ChangeUser add/remove order

Change the order in which the user is added and removed when changing
the user of a cached selector; Add the new user first, and remove the
old user next. This prevents the count of users dipping to 0 when
changing the only user of a cached selector, which is significant for
FQDN selectors, as the selector will be unregistered from the DNS
proxy whenever the user count reaches zero.

Fixes: #8117
Signed-off-by: Jarno Rajahalme <0f1ab0ac7dffd9db21aa539af2fd4bb04abc3ad4@covalent.io>

cilium/cilium,cilium/cilium,michi-covalent/cilium,cilium-team/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium