tooling: Optimize `config_validation` (#21607)

Signed-off-by: Ryan Northey <ryan@synca.io>

Mirrored from https://github.com/envoyproxy/envoy @ 2b2a08b23611a7a77942e1a203b24a0ebb1698df

BUILD

@@ -1,6 +1,6 @@
 # DO NOT EDIT. This file is generated by tools/proto_format/proto_sync.py.
 
-load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_descriptor_set", "proto_library")
 
 licenses(["notice"])  # Apache 2
 
@@ -323,3 +323,12 @@ filegroup(
     ],
     visibility = ["//visibility:public"],
 )
+
+proto_descriptor_set(
+    name = "v3_proto_set",
+    visibility = ["//visibility:public"],
+    deps = [
+        ":v3_protos",
+        ":xds_protos",
+    ],
+)