[prism] Support Attempted Metrics

[lostluck]

Prism doesn't currently populate Attempted metrics, just committed metrics, when returning metrics through Job Logs.

In principle, for completed jobs, the values should be identical. They should only be different while a Job is executing.

The short version: Committed metrics should be all metrics from ProcessBundleResponses, while tentative metrics are those plus anything from a ProcessBundleProgressResponse.

Metrics are accumulated here.
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/runners/prism/internal/jobservices/metrics.go#L483

This would allow the following Java Validates Runner tests to pass:

MetricsTest$AttemptedMetricTests.testAttemptedDistributionMetrics
MetricsTest$AttemptedMetricTests.testAttemptedCounterMetrics

[lostluck]

It looks like the root issue here is that the Loopback worker for Java doesn't propagate Runner Capabilities. This was surprising, but also not, as Java doesn't make use of loopback mode as much of the other SDKs. The ExternalWorker service needs to call the provision endpoint when available and override whatever it thinks it needs.

Basically, what was happening with the metrics was that Java was only sending the deprecated monitoring infos, instead of the short_id coded monitoring data. Prism doesn't support the infos (as all newer SDKs support it by default, and prism isn't meant to validate that slice of behavior). The metrics were thus going uninterpretted.