Extract common User MonitoringInfo URN parsing logic.

[https://github.com/apache/beam/blob/master/runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/fn/control/UserMonitoringInfoToCounterUpdateTransformer.java#L104](https://github.com/apache/beam/blob/master/runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/fn/control/UserMonitoringInfoToCounterUpdateTransformer.java#L104)

Logic from this PR can be utilized if PR gets merged prior to work on this ticket.

https://github.com/apache/beam/pull/7915/files#diff-2a6c540e8bf410b089793ea6efadb291R42

Imported from Jira [BEAM-6925](https://issues.apache.org/jira/browse/BEAM-6925). Original Jira may contain additional context.
Reported by: Ardagan.