fix(eventarc): update the API

#### eventarc:v1

The following keys were changed:
- schemas.Channel.properties.cryptoKeyName.description

Author: yoshi-automation

discovery/eventarc-v1.json

@@ -2466,7 +2466,7 @@
       }
     }
   },
-  "revision": "20250624",
+  "revision": "20250801",
   "rootUrl": "https://eventarc.googleapis.com/",
   "schemas": {
     "AuditConfig": {
@@ -2555,7 +2555,7 @@
           "type": "string"
         },
         "cryptoKeyName": {
-          "description": "Resource name of a KMS crypto key (managed by the user) used to encrypt/decrypt their event data. It must match the pattern `projects/*/locations/*/keyRings/*/cryptoKeys/*`.",
+          "description": "Optional. Resource name of a KMS crypto key (managed by the user) used to encrypt/decrypt their event data. It must match the pattern `projects/*/locations/*/keyRings/*/cryptoKeys/*`.",
           "type": "string"
         },
         "labels": {

src/apis/eventarc/v1.ts

@@ -180,7 +180,7 @@ export namespace eventarc_v1 {
      */
     createTime?: string | null;
     /**
-     * Resource name of a KMS crypto key (managed by the user) used to encrypt/decrypt their event data. It must match the pattern `projects/x/locations/x/keyRings/x/cryptoKeys/x`.
+     * Optional. Resource name of a KMS crypto key (managed by the user) used to encrypt/decrypt their event data. It must match the pattern `projects/x/locations/x/keyRings/x/cryptoKeys/x`.
      */
     cryptoKeyName?: string | null;
     /**