fix unit tests

Author: JoeWang1127

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonAutoPopulateFieldTestingStub.golden

@@ -1,6 +1,5 @@
 package com.google.auto.populate.field.stub;
 
-import com.google.api.core.BetaApi;
 import com.google.api.core.InternalApi;
 import com.google.api.gax.core.BackgroundResource;
 import com.google.api.gax.core.BackgroundResourceAggregation;
@@ -36,7 +35,6 @@ import javax.annotation.Generated;
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
 @Generated("by gapic-generator-java")
-@BetaApi
 public class HttpJsonAutoPopulateFieldTestingStub extends AutoPopulateFieldTestingStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();