fix: remove debug messages (#2552)

Change-Id: Ife688d7dc8e24ba5c4722bb3bc26401cae604d71 Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly: - [ ] Make sure to open an issue as a [bug/issue](https://togithub.com/googleapis/java-bigtable/issues/new/choose) before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea - [ ] Ensure the tests and linter pass - [ ] Code coverage does not decrease (if any source code was changed) - [ ] Appropriate docs were updated (if necessary) - [ ] Rollback plan is reviewed and LGTMed - [ ] All new data plane features have a completed end to end testing plan Fixes #<issue_number_goes_here> ☕️ If you write sample code, please follow the [samples format]( https://togithub.com/GoogleCloudPlatform/java-docs-samples/blob/main/SAMPLE_FORMAT.md).

Author: igorbernstein2

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/metrics/BigtableCloudMonitoringExporter.java

@@ -173,10 +173,8 @@ private CompletableResultCode doExport(Collection<MetricData> metricData) {
 
  // Skips exporting if there's none
  if (bigtableTimeSeries.isEmpty()) {
- System.out.println("skipping empty metrics: " + this.exporterName);
  return CompletableResultCode.ofSuccess();
  }
- System.out.println(bigtableTimeSeries);
 
  CompletableResultCode exportCode = new CompletableResultCode();
  bigtableTimeSeries.forEach(