datapath: Fix error propagation in bpf_lxc.
datapath: Fix error propagation in bpf_lxc.

handle_tail_ipv[4|6] both directly return raw error codes, but since
they are tail calls, they should be calling send_drop_notify() prior to
returning these error codes to translate to the appropriate drop return
code.

This was introduced as part of a refactor in
7575ba03ccaa5038255c8c1e5c31a8011ed9aaa1.

Fixes #20143

Signed-off-by: Harsh Modi <df6da1e9474c02880446de62c95d046881d5ca33@google.com>

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