docs(regen): update sample code to set total timeout, add API client header test

Author: yoshi-automation

google-cloud-container/src/main/java/com/google/cloud/container/v1/ClusterManagerSettings.java

@@ -94,8 +94,12 @@
  * <code>
  * ClusterManagerSettings.Builder clusterManagerSettingsBuilder =
  *     ClusterManagerSettings.newBuilder();
- * clusterManagerSettingsBuilder.listClustersSettings().getRetrySettings().toBuilder()
- *     .setTotalTimeout(Duration.ofSeconds(30));
+ * clusterManagerSettingsBuilder
+ *     .listClustersSettings()
+ *     .setRetrySettings(
+ *         clusterManagerSettingsBuilder.listClustersSettings().getRetrySettings().toBuilder()
+ *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .build());
  * ClusterManagerSettings clusterManagerSettings = clusterManagerSettingsBuilder.build();
  * </code>
  * </pre>

google-cloud-container/src/main/java/com/google/cloud/container/v1/stub/ClusterManagerStubSettings.java

@@ -110,8 +110,12 @@
  * <code>
  * ClusterManagerStubSettings.Builder clusterManagerSettingsBuilder =
  *     ClusterManagerStubSettings.newBuilder();
- * clusterManagerSettingsBuilder.listClustersSettings().getRetrySettings().toBuilder()
- *     .setTotalTimeout(Duration.ofSeconds(30));
+ * clusterManagerSettingsBuilder
+ *     .listClustersSettings()
+ *     .setRetrySettings(
+ *         clusterManagerSettingsBuilder.listClustersSettings().getRetrySettings().toBuilder()
+ *             .setTotalTimeout(Duration.ofSeconds(30))
+ *             .build());
  * ClusterManagerStubSettings clusterManagerSettings = clusterManagerSettingsBuilder.build();
  * </code>
  * </pre>