changelog: migrate dynamic_modules entry to per-file layout

Signed-off-by: Basundhara Chakrabarty <basundhara17061996@gmail.com>

Author: basundhara-c

changelogs/current/new_features/dynamic_modules__added-cluster-lb-context-get-host-stat.rst

@@ -0,0 +1,4 @@
+Added the ``envoy_dynamic_module_callback_cluster_lb_context_get_host_stat`` ABI callback so
+custom cluster load balancers can read per-host counters and gauges at request time inside
+``envoy_dynamic_module_on_cluster_lb_choose_host``. The Rust SDK exposes this as
+``ClusterLbContext::get_host_stat``.