Add constraints in order to use led with webrtc bots.

This is meant to fix this error:
bad request: build: constraints for chromium:webrtc.fyi not found

Bug: None
Change-Id: I59f7f12560caf6c87d608da0c916ef3d51eb516c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6574474
Reviewed-by: Mirko Bonadei <mbonadei@chromium.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#1463323}

infra/config/generated/luci/cr-buildbucket.cfg

@@ -134259,6 +134259,10 @@ buckets {
       }
     }
   }
+  constraints {
+    pools: "luci.webrtc.ci"
+    service_accounts: "webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
+  }
 }
 buckets {
   name: "webrtc.fyi"
@@ -135376,6 +135380,10 @@ buckets {
       }
     }
   }
+  constraints {
+    pools: "luci.webrtc.ci"
+    service_accounts: "webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
+  }
 }
 common_config {
   builds_notification_topics {

infra/config/generated/luci/realms.cfg

@@ -785,6 +785,7 @@ realms {
   bindings {
     role: "role/buildbucket.builderServiceAccount"
     principals: "user:chromium-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
+    principals: "user:webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
   }
   bindings {
     role: "role/buildbucket.creator"
@@ -834,6 +835,7 @@ realms {
   bindings {
     role: "role/buildbucket.builderServiceAccount"
     principals: "user:chromium-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
+    principals: "user:webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"
   }
   bindings {
     role: "role/buildbucket.creator"

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

@@ -10,6 +10,10 @@ load("//lib/xcode.star", "xcode")
 
 luci.bucket(
     name = "webrtc.fyi",
+    constraints = luci.bucket_constraints(
+        pools = ["luci.webrtc.ci"],
+        service_accounts = ["webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"],
+    ),
     bindings = [
         luci.binding(
             roles = "role/buildbucket.reader",

infra/config/subprojects/webrtc/webrtc.star

@@ -9,6 +9,10 @@ load("//lib/targets.star", "targets")
 
 luci.bucket(
     name = "webrtc",
+    constraints = luci.bucket_constraints(
+        pools = ["luci.webrtc.ci"],
+        service_accounts = ["webrtc-ci-builder@chops-service-accounts.iam.gserviceaccount.com"],
+    ),
     bindings = [
         luci.binding(
             roles = "role/buildbucket.reader",