feat: (metrics) initialize metrics handler in temporal sdk if provided

[laouji]

relates to: ENG-1546

after talking to Temporal customer support they recommended enabling temporal sdk metrics in order to better measure worker latency and decide if we are scheduling too much work for our workers to handle

The Schedule-To-Start time of an Activity Task in seconds. A Schedule-To-Start Timeout can be set when an Activity Execution is spawned. This metric is useful for ensuring Activity Tasks are being processed from the queue in a timely manner. Some SDKs may include the activity_type label, but the metric should not vary by type, as it does not influence the rate at which tasks are pulled from the queue.

source: https://docs.temporal.io/references/sdk-metrics#activity_schedule_to_start_latency