Background
The WikiLambda API instrument is the only instrument that uses EventLogging::getMetricsPlatformClient() and the MetricsClient class. Migrating this instrument to use the Test Kitchen SDK will unblock the deprecation and removal of that method and class.
AC
- The instrument config is added to Test Kitchen UI
- The instrument is rewritten to use InstrumentManager#getInstrument()
- The stream config is updated to reflect management via Test Kitchen
- https://gerrit.wikimedia.org/g/operations/mediawiki-config/+/4799083316924ee510febc57f238f8140c8ff7fb/wmf-config/ext-EventStreamConfig.php#3191
- Remove producers.metrics_platform_client.provide_values property
- Remove sample property
- Add a link to the instrument config in Test Kitchen UI