feat: [run]support manual instance count in Cloud Run for manual scal…

…ing feature (#5821)

* feat:support manual instance count in Cloud Run for manual scaling feature

PiperOrigin-RevId: 697723876

Source-Link: googleapis/googleapis@c6eb517

Source-Link: googleapis/googleapis-gen@7dd2077
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packages/google-cloud-run/protos/google/cloud/run/v2/vendor_settings.proto

@@ -158,6 +158,12 @@ message ServiceScaling {
 
   // Optional. The scaling mode for the service.
   ScalingMode scaling_mode = 3 [(google.api.field_behavior) = OPTIONAL];
+
+  // Optional. total instance count for the service in manual scaling mode. This
+  // number of instances is divided among all revisions with specified traffic
+  // based on the percent of traffic they are receiving.
+  optional int32 manual_instance_count = 6
+      [(google.api.field_behavior) = OPTIONAL];
 }
 
 // Hardware constraints configuration.