rbac: Add per-policy stats to HTTP filter (#32313)

This adds additional stats for `rules` and `shadow_rules` in the HTTP-based RBAC filter.

Fixes #32129

---------

Signed-off-by: Henry Wang <henry.wang@datadoghq.com>

Mirrored from https://github.com/envoyproxy/envoy @ 5eccc35176a77633c98bd96baa64d15bd3c5fe2f

envoy/extensions/filters/http/rbac/v3/rbac.proto

@@ -22,7 +22,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // [#extension: envoy.filters.http.rbac]
 
 // RBAC filter config.
-// [#next-free-field: 7]
+// [#next-free-field: 8]
 message RBAC {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.config.filter.http.rbac.v2.RBAC";
@@ -67,6 +67,9 @@ message RBAC {
   // This is useful to distinguish the stat when there are more than 1 RBAC filter configured with
   // shadow rules.
   string shadow_rules_stat_prefix = 3;
+
+  // If track_per_rule_stats is true, counters will be published for each rule and shadow rule.
+  bool track_per_rule_stats = 7;
 }
 
 message RBACPerRoute {