make ErrorTypeUtil package private so we can remove without it being a breaking change.

Author: ldetmer

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/telemetry/ErrorTypeUtil.java

@@ -22,11 +22,9 @@
  * replaced with gax version when ready work tracked in
  * https://github.com/googleapis/google-cloud-java/issues/12105
  */
-@VisibleForTesting
-public class ErrorTypeUtil {
+class ErrorTypeUtil {
 
-  @VisibleForTesting
-  public enum ErrorType {
+  enum ErrorType {
     CLIENT_TIMEOUT,
     CLIENT_CONNECTION_ERROR,
     CLIENT_REQUEST_ERROR,

java-bigquery/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/it/ITOpenTelemetryTest.java

@@ -15,7 +15,6 @@
  */
 package com.google.cloud.bigquery.it;
 
-import static com.google.cloud.bigquery.telemetry.ErrorTypeUtil.ErrorType;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -215,7 +214,7 @@ public void testClientErrorAndRetriesTraced() {
         assertEquals(
             "java.net.UnknownHostException", attrs.get(BigQueryTelemetryTracer.EXCEPTION_TYPE));
         assertEquals(
-            ErrorType.CLIENT_CONNECTION_ERROR.toString(),
+            "CLIENT_CONNECTION_ERROR",
             attrs.get(BigQueryTelemetryTracer.ERROR_TYPE));
         assertEquals(
             "UnknownHostException: invalid-host-name-12345.com",