docs: update docs with L3/L4 drop/forward metrics
docs: update docs with L3/L4 drop/forward metrics

Fixes: #4171
Signed-off by: Manali Bhutiyani <manali@covalent.io>

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