policy: add debug log when error from `updateEndpointsCaches` is non-nil
policy: add debug log when error from `updateEndpointsCaches` is non-nil

This error is harmless for the most part, but means that an endpoint has been
deleted or has a nil identity while we are still trying to update the caches in
the rules for it, which is not optimal functionality.

Signed-off by: Ian Vernon <ian@cilium.io>

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