[EXAMPLES] Make BinaryClassificationMetricsExample consistently print the metrics on driver's stdout

Some RDDs in this example (e.g., precision, recall) call println without calling collect.
If the job is under local mode, it sends the data to the driver node and prints the metrics on the driver's stdout.
However if the job is under cluster mode, the job prints the metrics on the executor's stdout.
It seems inconsistent compared to the other metrics nothing to do with RDD (e.g., auPRC, auROC) since these metrics always output the result on the driver's stdout.
All of the metrics should output its result on the driver's stdout.