Regenerate language client: remove unused imports (#4071)

Author: yoshi-automation

google-cloud-clients/google-cloud-language/src/test/java/com/google/cloud/language/v1/LanguageServiceSmokeTest.java

@@ -15,7 +15,6 @@
  */
 package com.google.cloud.language.v1;
 
-import com.google.cloud.language.v1.Document.Type;
 import com.google.common.base.Preconditions;
 import java.util.logging.Level;
 import java.util.logging.Logger;

google-cloud-clients/google-cloud-language/src/test/java/com/google/cloud/language/v1beta2/LanguageServiceSmokeTest.java

@@ -15,7 +15,6 @@
  */
 package com.google.cloud.language.v1beta2;
 
-import com.google.cloud.language.v1beta2.Document.Type;
 import com.google.common.base.Preconditions;
 import java.util.logging.Level;
 import java.util.logging.Logger;