docs: Adjust wording around service accounts and control planes

Google APIs · copybara-github · commit f0cec0b20173 · 2023-04-06T17:43:07.000-07:00
PiperOrigin-RevId: 522482855
diff --git a/google/cloud/workstations/v1beta/workstations.proto b/google/cloud/workstations/v1beta/workstations.proto
@@ -403,10 +403,11 @@ message WorkstationConfig {
       // The name of a Compute Engine machine type.
       string machine_type = 1;
 
-      // Email address of the service account that will be used on VM instances
-      // used to support this config. This service account must have permission
-      // to pull the specified container image. If not set, VMs will run without
-      // a service account, in which case the image must be publicly accessible.
+      // Email address of the service account used on VM instances
+      // used to support this configuration. If not set, VMs run with a
+      // Google-managed service account. This service account must have
+      // permission to pull the specified container image; otherwise, the image
+      // must be publicly accessible.
       string service_account = 2;
 
       // Network tags to add to the Compute Engine machines backing the
