Allow WebRTC admins to trigger WebRTC ci bots.

Goal is to be able to trigger led runs and simplify the debugging of https://crbug.com/418717425.

Bug: None
Change-Id: I27abce4c18b6158fab712de7c61774dd759ce81c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6573734
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Reviewed-by: Ilya Nikolaevskiy <ilnik@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1463275}

infra/config/generated/luci/realms.cfg

@@ -841,6 +841,7 @@ realms {
   bindings {
     role: "role/buildbucket.triggerer"
     principals: "group:project-chromium-ci-schedulers"
+    principals: "group:project-webrtc-admins"
   }
   bindings {
     role: "role/scheduler.owner"

infra/config/subprojects/webrtc/webrtc.fyi.star

@@ -17,7 +17,10 @@ luci.bucket(
         ),
         acl.entry(
             roles = acl.BUILDBUCKET_TRIGGERER,
-            groups = "project-chromium-ci-schedulers",
+            groups = [
+                "project-chromium-ci-schedulers",
+                "project-webrtc-admins",
+            ],
         ),
         acl.entry(
             roles = acl.BUILDBUCKET_OWNER,