Re-enable currency service metrics

[damemi]

Metrics from the currency app were filtered due to open-telemetry/opentelemetry-demo#1330, which has been resolved upstream. Re-enabling this now so we can get telemetry from all available services.

[damemi]

Opening this as a draft for now because I'm still seeing the issue with the currency service in the collector logs:

2024-05-08T19:11:46.314Z	error	exporterhelper/queue_sender.go:125	Exporting failed. No more retries left. Dropping data.	{"kind": "exporter", "data_type": "metrics", "name": "googlemanagedprometheus", "error": "rpc error: code = InvalidArgument desc = One or more TimeSeries could not be written: One or more points were written more frequently than the maximum sampling period configured for the metric.: prometheus_target{namespace:otel-demo,cluster:autopilot-cluster-2,instance:adc2c5ec-7cad-4729-a616-0f21b55ec738,job:opentelemetry-demo/currencyservice,location:us-central1} timeSeries[0-2]: prometheus.googleapis.com/app_currency_counter_total/counter{otel_scope_name:app_currency,otel_scope_version:1.3.0,currency_code:USD}\nerror details: name = Unknown  desc = total_point_count:3  errors:{status:{code:9}  point_count:3}", "dropped_items": 1}

it's pretty noisy, so I don't think we want to merge it in yet. but this will be part of the fix

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This PR was marked stale due to lack of activity. It will be closed in 7 days.

[github-actions]

Closed as inactive. Feel free to reopen if this PR is still being worked on.